[design] remove drawer

[stefan-niedermann]

• [ ] the main activity should display the content of "My Accounts"
• [ ] The content of the main activity should be in a swipe to refresh layout, which replaces the "Sync Now" entry of the drawer
• [ ] The "add account" entry of the drawer should be moved into a floating action button displayed at the main activity because it is the most important interaction a user will have with the app
• [ ] The "settings" should move as an icon to the top right of the bar - use this icon from Material:

• [ ] "App infos and permissions" - two options (i prefer the second): Move the entry into the settings OR get rid of it completely, since it is android default and accessible from outside of the app.
• [ ] "Rate us!" - Move it to the top right, next to settings with an star as icon OR (preferred:) move it into the settings, that's where users will look for it usually
• [ ] Remove the drawer