Initial AppView Implementation

[jvalkeal]

Opinionated app view having main content, menubar and statusbar. Usually this type of container have key bindings for navigating between in a main content. We start with simple left/right arrows.

┌─────────────────────────────┐
│           Menubar           │
├─────────────────────────────┤
│        Main content         │
│                             │
│                             │
├─────────────────────────────┤
│          Statusbar          │
└─────────────────────────────┘

• Menu system
• Status system
• Events for navigation