Time & date, system events and much more (#152)

## Time & Date
- Added time to statusbar widget
- Added Time & Date Settings app
- Added TimeZone app for selecting TimeZone
- Added `tt::time` namespace with timezone code

## Other changes

- Added `SystemEvent` to publish/subscribe to system wide (e.g. for init code, but also for time settings changes)
- Changed the way the statusbar widget works: now there's only 1 that gets shown/hidden, instead of 1 instance per app instance.
- Moved `lowercase()` function to new namespace: `tt::string`
- Increased T-Deck flash & PSRAM SPI frequencies to 120 MHz (from 80 MHz)
- Temporary work-around (+ TODO item) for LVGL stack size (issue with WiFi app)
- Suppress T-Deck keystroke debugging to debug level (privacy issue)
- Improved SDL dependency wiring in various `CMakeLists.txt`
- `Loader` service had some variables renamed to the newer C++ style (from previous C style)

Tactility/Source/service/loader/Loader.h

@@ -24,7 +24,7 @@ typedef enum {
  * @param[in] blocking whether this call is blocking or not. You cannot call this from an LVGL thread.
  * @param[in] parameters optional parameters to pass onto the application
  */
-void startApp(const std::string& id, bool blocking = false, std::shared_ptr<const Bundle> _Nullable parameters = nullptr);
+void startApp(const std::string& id, bool blocking = false, const std::shared_ptr<const Bundle>& _Nullable parameters = nullptr);
 
 /** @brief Stop the currently showing app. Show the previous app if any app was still running. */
 void stopApp();