Resource cleanups part 2

This is on top of !807 (merged). We expand the tests to process the main loop some more to catch missing cancellations of dbus calls and idle callbacks. In order to not opencode that everywhere PhoshStatusIcon and PhoshManager get idle_init helpers. We then lower the priority of some messages indicating callback cancelation (which is not an error) or the total lack of a DBus service (also not an error) so tests can trap on warnings.

This does not yet give us a restartable libphosh but gets us way closer. (works now)

Signed-off-by: Guido Günther guido.gunther@puri.sm