Gradebook data has (mostly) been parsed. Just need to inflate the layout.

Managed to parse the JSON for the gradebook data. Remaining task is to
dynamically add the views to the layout for each module's gradebook. Also
added a logout button to the home page since the original logout button
in the drawer is too far down.

Signed-off-by: nicholaslum444 <nicholaslum444@hotmail.com>