Add Start on boot setting and Add exit notification action
BUG: Currently the app starts on boot without users consent and runs in background. But what this PR does is add a
Start on Boot switch in settings to ask the user whether he wants this app to start on boot or not.
BUG: Also many users gets annoyed by that continues
Not connected to any device Notification, So this PR adds an
Exit app button as an intent(when no device is connected) so the user can exit the app whenever they want, Instead of force stopping the app from settings.
NOTE: I am very noob to java so please check for any errors beforehand, As nobody reacted to the issues on bugs.kde.org so I decided to step in myself and fix these bugs.