RemoteBridge: Some changes

- Fix: Bugs in addMail
- Fix: Some CS issues fixed
- Added action: check_mail which checks if a mailaccount still exists
- Added action: delete_mail
Revert "RemoteBridge: Some changes"

This reverts commit ed2c9f7a9b7bff1db6422aeb22d28a220c2e3f11.
Merge remote-tracking branch 'origin/master'