Overhaul the UI to general usability

[nazrinharris]

This'll change a lot of the screens, and make the app feel relatively like an app, rather than a mashup of whatever I cooked up in the lab.

Initial Deeds

• [x] #103

The Crux

• [x] #104
• [x] Implement the MainScreen, where it'll house the bottom sheet and the four tabs.
• [x] Add a DashboardScreen, AccountsScreen, AnalyticsScreen and ProfileScreen
• [x] Add a Recent Transactions section in DashboardScreen
• [x] Make AccountsScreen prettier.
• [x] Make ProfileScreen amicable
• [x] #86
• [x] #110
• [x] #111
• [x] #112
• [x] #117

Others

• [x] #66
• [x] #108
• [x] #107
• [x] #105
• [x] #114

Bugs

• [x] #106
• [x] #109
• [x] #113
• [x] #116