fix(notification): should display the right callee name

Before:
- When sending the call notification, the message only contained room identifier
- Call API: GET /call/:username/room/:room

After:
- Now, when sending the call notification the message contained callee, caller, roomId
- Call API: POST /call. The API expect callee, caller, roomId.
refactor(notifcation); remove logging
refactor(API): remove broken utility function

Side effects:
- generalRoutes.notifyOtherUser route handler is merged into apiRoutes.call route handler

Notes:
- utility to check if the callee is online or not is unimplemented yet
Merge branch 'fix-call-notification'