feat(desktop-ui): Command/ctrl + comma goes to Settings view

[matthewdiamant]

A very standard shortcut is Command + comma (or Ctrl + comma) to go to an App's settings or preferences (try it out on Slack, Notion, Discord, or your favorite app).

Also adding Settings to the app menu, after the About item, which is also where Chrome/Notion/Slack has it.

Also, adding the general ability to change views with the 'set-view' message.