Removed:
- Battery Visualizer -> Too much real estate taken, not so useful, device battery visible in main header and overview panel.
- Dash Separator -> Useless
- Growing text -> Relic from early testing days
- Header -> Replaced by `main_header` and `main_footer`.

Added:
- Documentation
- Main header components (battery and db, WIP: map and network)
- Main footer
- Locations of interest database (and related data classes).

Changed:
- DataHandler (WIP, remove reliance on latest packet, use database)
- Renamed DatabaseHandler to MainDatabaseHandler (only storing LogAir device data).
- Tweaks in overview widgets to remove tree clutter.