New version scheme

Also log the offending JID on avatar decoding issue

See merge request gajim/gajim!158

We changed the version format

Mac and Windows dont have dbus available

Fix invalid dev version string

See merge request gajim/gajim!157

Desktop files: add information for translators

See merge request gajim/gajim!156

Create desktop and appdata files in build directory

See merge request gajim/gajim!155

This was somehow lost once we implemented random resource strings
Although its good that initally a random resource is chosen, it
still should persist across sessions.

This helps to kill zombie client connections on the server because
most servers kill the old session once a new with the same resource
connects

Also dont notify the user about resource conflicts if no custom
resource is set. We should not expect users to know about resources
and what they are used for as long as possible.

Add MAM for MUCs

See merge request gajim/gajim!152

A stanza-id is only unique within a specific archive
This adds the archive jid to the query

- move it into message_archiving.py

- A Migration from last_mam_id config value is included

When we search for duplicated stanza-ids we have to do it
in the context of an account

New visible func

Closes #8670

See merge request gajim/gajim!153

Use Gio.NetworkMonitor for reconnecting

See merge request gajim/gajim!149

Add symbolic icon

See merge request gajim/gajim!151

Fix #8749: Misleading error message when joining a room

Closes #8749

See merge request gajim/gajim!150

Distinguish between 'item-not-found' and 'remote-server-not-found'

Fixes #8749

- Some plugins do not depend on gui extension points and need the
roster to be initialized