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/src/lv_screenshot.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "lvgl.h"
+#include <stdbool.h>
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    LV_100ASK_SCREENSHOT_SV_BMP = 0,
+    LV_100ASK_SCREENSHOT_SV_PNG = 1,
+    LV_100ASK_SCREENSHOT_SV_LAST
+} lv_100ask_screenshot_sv_t;
+
+bool lv_screenshot_create(lv_obj_t* obj, lv_img_cf_t cf, lv_100ask_screenshot_sv_t screenshot_sv, const char* filename);
+
+#ifdef __cplusplus
+} /*extern "C"*/
+#endif