Execute the edit callback function in a thread. By executing it in a thread
we don't have to wait for longer validation procedures to finish to
continue updating the UI. This is most notable in the MoveGamePopUp
which is heavy on disk IO.
Because we cannot use special text formatting in a thread, the
indicator messages have been reworked while also becoming extensible.
A dictionary of extended reasons can be specified through the
`IndicatorLineEdit.extend_reasons()` method.
The dictionary has to follow the following format
```
python
{
MyIndicatorReasons.REASON: self.tr("Reason message")
MyIndicatorReasons.OTHER_REASON: self.tr("Other reason message")
}
```
In the above example `MyIndicatorReasons` is a subclass of `IndicatorReasons`
which should be specified as follows
```
python
MyIndicatorReasons(IndicatorReasons):
REASON = auto()
OTHER_REASON = auto()
```
Note: the `__update_widget()` method, while it doesn't have any visible delay
has the potential for improvement. I didn't do it because it felt like
premature optimization.
MoveGamePopUp: update it to use RareGame and it's signals
RareGame: Add `install_path` attribute and change `needs_verification` setter
Now both setters will update the local `igame` attribute and save it too.
MoveWorker: Update it to use RareGame.
Other changes include moving "same-drive" moving into the worker and using
`os.path` methods instead of `PathLib`
SteamGrades: Remove worker, it is implemented in RareGame now.
instead of adding them again to the layout. Move game should still
switch to RareGame, similar to the way it works for verifing.
Also add non-functional "Import Game" button
