Screenshot app & service (#42)

- Added screenshot app & service (PC-only for now)
- Updated docs with screenshots and new device photo
- Add fake statusbar icons for PC/sim build
- added `lv_screenshot` library based on `lv_100ask_screenshot` from https://github.com/100askTeam/lv_lib_100ask
- T-Deck WiFi is now allocated into SPI RAM
- Created `tt_service_find()` to find services by their id

libs/lv_screenshot/README.md

@@ -0,0 +1,12 @@
+## lv_screenshot
+
+This library is adapted from the lv_100ask_screenshot library from 100ask on [GitHub](https://github.com/100askTeam/lv_lib_100ask).
+
+The original license is available [here](LICENSE-original).
+
+## Features
+
+- Save LVGL screen objects (full screen) as image files: lv_scr_act(),layer_sys(),layer_top()
+- Capture and save the specified LVGL object and its children as an image file
+- Supported save as: BMP, PNG, JPG
+- more todo...