When transferring messages within one server the local cache
of the source folder did not have deleted the moved message,
while it was no longer available in that folder.

ESources were always set enabled, even though their corresponding part
in the Collection extension could be disabled, like in GOA/UOA, which
led to confusion and misbehaviour.

When an account is offline, then its locally stored messages
should not be removed due to expiry, such thing should be
done only in online, otherwise it could make message available
in one second and then re-selecting it a second later it being
unavailable, which is rather confusing and unexpected.

This file is not needed since the switch to CMake, where the languages
are detected by the .po file existence, but as I forgot to remove them
in the time of the switch...