When the `GVFS_DEBUG` envar is set, list of discovered devices is printed
on each reload i.e. each 15 seconds currently. This spamming is unwanted.
Let's print this info only if the `GVFS_WSDD_DEBUG` envar is set.

The wsdd backend enumerates also printers and other unwanted devices now.
It is now possible to request just devices of concrete types thanks to the
https://github.com/christgau/wsdd/pull/189 request. Let's specify the
`pub:Computer` type to filter out those unwanted devices.

Related: !186 (comment 1854469)

Related: !148

This reverts commit 70128710. It turned
out that this argument doesn't exist which causes build issues on systems
that don't use GNU C Library.

Fixes: #712

Currently, the unmount operation fails for mount paths that are not
propagated from udisks (e.g. FUSE) and contain non-ASCII characters.
This is because the mount path is escaped by the `g_strescape` function
that drops non-ASCII characters among others. It is not clear why this
function was used here, but it seems right to use the `g_shell_quote`
function instead. Let's do so to fix unmounting in the mentioned cases.

Fixes: #706

The commit 428dfb09 defined the `default_options` argument for a second
time by mistake. It causes build warnings currently. Let's merge both
the `default_options` arguments to get rid of those warnings.

Currently, the WSDD backend uses target URIs based on IP addresses.
This is not ideal also because display names are not propagated to
the SMB backend and mount prompts show just IP addresses. Let's try
to lookup hostnames based on device names.

Related: #506

After the NT1 protocol deperecation, the "Other Locations" view (ie.
network backend) doesn't contain Windows devices in the most cases.
Let's display files from the wsdd backend to make the Windows devices
available again.

The wsdd project seemingly doesn't invalidate already discovered devices.
Consequently, the backend may list unavailable devices. This is especially
problem during network changes. Let's force the wsdd project to invalidate
the results when network change is detected. Once this is fixed on the wsdd
side, this commit can be reverted.

Related: #506

This backend implements Web Service Device Discovery protocol support to
list (not only) Windows devices. It uses the wsdd project
(https://github.com/christgau/wsdd) and requires wsdd binary to be available
in `$PATH`.

Fixes: #506

The network backend shows results from other backends. So the same service
may be propagated by different backends. This become bigger problem with
the merged SMB results and with the upcoming WSDD support. The problem is
that each backend uses different URIs (e.g. "smb://foo.local:445",
"smb://foo", "smb://127.0.0.1"), so it can't be easily compared. Resolving
URIs just for their comparison doesn't sound like a good idea. Let's make
an assumption that the files with the same display name and scheme point
to the same service and just keep the first one. This approach should work
fine in most cases.

The "Windows Network" folder is always shown despite the fact that
it is empty in most cases given the NT1 protocol deprecation. Let's
directly list available devices if they are any instead of showing
that folder. The same is done by default for DNS-SD services already.

Fixes: #679
Related: nautilus#2785

The files provided by the dns-sd backend are displayed merged by default.
The services from the smb browse backend are hidden in the "Windows Network"
folder except those from the default domain (which hasn't worked reliably so
far). Let's add a possiblity to show the "Windows Network" content merged
similar to what is done with the dns-sd files. As a part of this change,
let's don't show the default domain results merged when the "Windows Network"
folder is shown to simplify handling a bit.

Related: #307

As a preparation for the follow up changes, let's rename the `GDnsSdDisplayMode`
enum to `GVfsBackendNetworkDisplayMode`. This enum is anyway used by the network
backend only.

There is a lot of duplicated code currently. Let's add a helper function
to add network backend files from a certain directory to simplify the
code a bit. This is a preparation for the follow up changes.

The `target_uri` strings are not compared currently by the
`network_file_equal` function. I'm not sure whether this is a problem
currently, but it might be in the future. Let's compare those string
as well for sure.

The display name comparison in the `network_file_equal` function is
overcomplicated currently. Let's use `g_strcmp0` to simplify the code
a bit.

The filename prefix for DNS-SD results is currently: `dnssd-domain-`.
Let't change that to `dnssd-server-` to be in line with the SMB files.

The link URI for SMB servers is created over string concatenation.
Although this works currently, it may not work	in the future. Let's
instead use  the G_FILE_ATTRIBUTE_STANDARD_TARGET_URI attribute that
is dedicated to this purpose.

The `g_idle_add` function is called from various places to start the
`recompute_files` on idle. Let's add a helper function to simplify the
code a bit.

The error variable is passed to the `g_file_mount_enclosing_volume_finish`
function and freed immediately after that. Let's drop this redundant error
handling.

When smb-related gsettings keys are changed, the `recompute_files`
function is called directly regardless of the fact that it might be
already scheduled. It is not a big deal as the gesttings keys are not
meant to be changed often, though the rest of the code uses a better
approach. It schedules the `recompute_files` function execution only
if it is not already. Let's use that approach in this case as well.

The network backend files are reloaded only with file monitor events.
However, the smb browse backend doesn't support monitoring and thus
some files may not be present or may be invalid. For this reason,
always reload the network backend files before enumerating.

The smb browse backend doesn't have monitor support, but the network
backend creates directory monitos for SMB locations anyway. Let's get rid
of this dead code in preparation for future changes.

Although, the `G_DNS_SD_DISPLAY_MODE_DISABLED` enum value is valid
for the `display-local` gsettings key, it is not handled by the network
backend currently. Let's hide the DNS-SD services when this option
is used.

It is not obvious that the display-local gsettings key affect the
network:/// output and what the concrete options do. Let's try to
make this a bit clearer.

The glib, glib-networking, and libsoup packages are built from sources
currently. This is not needed now. Let's use the official Fedora packages
instead.

Related: !192

The `/etc/containers/storage.conf` configuration file is no longer
available. Let'd drop that to fix the update-image job.

Related: nautilus!1091 (comment 1696433)

gcr3 is now obsolete. Let's port to gcr4.