Fixes and improvements (#132)

- Fix glitch when turning on WiFi: It would temporarily show "No networks found" right before starting the first scan.
- Fix spinner to use Assets.h
- Replace statusbar battery icons 
- Better statusbar icon for when WiFi is on but not connected
- Replace statusbar WiFi icons and Wifi Manage RSSI/lock icons
- Fix for crash when timer is null in I2cScanner
- Deprecate Spacer
- Fixes for toolbar layout (simplified)
- Improved ImageViewer app: center image and add filename text on the bottom
- Add LV debug params to sdkconfig.developer
- Disabled LV spinner, msgbox and window widgets. These have equivalents in Tactility.

Tactility/Source/app/files/Files.cpp

@@ -219,7 +219,7 @@ static void onShow(AppContext& app, lv_obj_t* parent) {
     lv_obj_set_flex_flow(parent, LV_FLEX_FLOW_COLUMN);
 
     lv_obj_t* toolbar = lvgl::toolbar_create(parent, "Files");
-    lvgl::toolbar_add_action(toolbar, LV_SYMBOL_UP, &onNavigateUpPressed, nullptr);
+    lvgl::toolbar_add_button_action(toolbar, LV_SYMBOL_UP, &onNavigateUpPressed, nullptr);
 
     data->list = lv_list_create(parent);
     lv_obj_set_width(data->list, LV_PCT(100));