app-module:
- Implement `AppStartContext` to reduce amount of `app_start_` and `app_exec` functions: replace them with `app_start_with_context()`
- Add support for environment variables when starting apps
- Implement support for environment variables for apps
graphics-module:
- Add this new module
- Move font-module code into this module
- Implement pixel_buffer
apps:
- Terminal app: reduce memory usage by only buffering a single row of characters, and try to buffer in IRAM when possible. Implement new pixel_buffer.
- App List: Mark apps as favourite to pin them on top. Use touch or press "x" key.
- App List: Add toolbar button that shows alert dialog with info about using favourites
