Rework the StateDialogActivity (fixes #1814)

[fps]

Possible fix for https://github.com/syncthing/syncthing-android/issues/1814

• Add a neutral button to simply dismiss the dialog and close the app (but leave it in the tasks list)
• Make the exit button stop the service and exit the app, removing it from the task list

[fps]

Thanks for the review! Yeah, you're right about it being conditional on that preference. I'll have to ponder this for a little while..

[fps]

I decided to remove the "dismiss" button again and basically make the exit button in the dialog work like the exit button in the DrawerFragment (i.e. stop the service only when it's not set to start at boot and remove the task from the tasklist in either case.)

[imsodin]

There's no exit button at all in the drawer menu when set to start at boot. And generally I don't think it's a good idea having a button (not deactivated) which does nothing.

[fps]

Hi again, the exit button does exist in the StateDialogActivity dialog though, even when the service is set to start at boot. So do you argue the exit button should not exist in that dialog either in case the service is set to start at boot?

[imsodin]

Doesn't exist for me:

Sorry again for the super long reaction time, I'll need to make a point of dedicating some fixed time to Syncthing - I really like doing it, it's just hard to allocate the time (that sounds like BS even to myself :P ).

[fps]

Hi! No problem at all. There is no hurry :) I guess it's me running an older version again.. I will think about the dialog a bit more then...