Icons are generated from Source using App Icon Preview

When we are connected to the server we need to set some things up
before we send our initial available presence. The new state makes
it possible for other code to difference between when we are connected
and when we are available.

For example other code should not send a presence before we requested
the roster.

Fixes #9983

- Let nbxmpp handle responding to entity caps requests
- Move code into Caps module

Fixes #10044

Otherwise its not really portable if it stores data in the system keyring

The row was initialized with the show value instead of using
the helper function get_connection_status()

Fixes #10035

When this method is called we are already disconnected

Otherwise the resource is changed on first connect which can trigger
the relogin check in the Accounts Dialog