Keyboard Shortcuts Overhaul

Every action should be able to be mapped to a shortcut. Right now there is a very limited amount of shortcuts.

Some missing ones:
- New Mail
- Close/Open Sidebar

Selected mail:
- Archive, Spam, Bin, Label, Move to, etc

These are just off the top of my head, I’m sure there’s more.

Also the existing shortcuts need to do a better job at setting the user up for the action.
For example, when I’m focused on an email, and i hit “R” (which is reply) This should automatically focus the text box so i can start typing my reply.