Merge develop into main (#327)

## New features
- Implemented support for app packaging in firmware and `tactility.py`: load `.app` files instead of `.elf` files. Install apps remotely or via `FileBrowser`.
- Ensure headless mode works: all services that require LVGL can deal with the absence of a display
- Service `onStart()` is now allowed to fail (return `bool` result)
- Added and improved various file-related helper functions

## Improvements
- Completely revamped the SystemInfo app UI
- Improved Calculator UI of internal and external variant
- Fix Chat UI and removed the emoji buttons for now
- Fix for toolbar bottom padding issue in all apps

## Fixes
- Fix for allowing recursive locking for certain SPI SD cards
& more

ExternalApps/Calculator/main/Source/Calculator.cpp

@@ -145,6 +145,7 @@ void Calculator::resetCalculator() {
 void Calculator::onShow(AppHandle appHandle, lv_obj_t* parent) {
     lv_obj_remove_flag(parent, LV_OBJ_FLAG_SCROLLABLE);
     lv_obj_set_flex_flow(parent, LV_FLEX_FLOW_COLUMN);
+    lv_obj_set_style_pad_row(parent, 0, LV_STATE_DEFAULT);
 
     lv_obj_t* toolbar = tt_lvgl_toolbar_create_for_app(parent, appHandle);
     lv_obj_align(toolbar, LV_ALIGN_TOP_MID, 0, 0);
@@ -187,10 +188,9 @@ void Calculator::onShow(AppHandle appHandle, lv_obj_t* parent) {
     lv_obj_set_style_pad_all(buttonmatrix, 5, LV_PART_MAIN);
     lv_obj_set_style_pad_row(buttonmatrix, 10, LV_PART_MAIN);
     lv_obj_set_style_pad_column(buttonmatrix, 5, LV_PART_MAIN);
-    lv_obj_set_style_border_width(buttonmatrix, 0, LV_PART_MAIN);
+    lv_obj_set_style_border_width(buttonmatrix, 2, LV_PART_MAIN);
     lv_obj_set_style_bg_color(buttonmatrix, lv_palette_main(LV_PALETTE_BLUE), LV_PART_ITEMS);
 
-    lv_obj_set_style_border_width(buttonmatrix, 0, LV_PART_MAIN);
     if (lv_display_get_horizontal_resolution(nullptr) <= 240 || lv_display_get_vertical_resolution(nullptr) <= 240) {
         //small screens
         lv_obj_set_size(buttonmatrix, lv_pct(100), lv_pct(60));