Externalize level (#2596)

* removing ability to focus on RSSI bars and to launch level app, until a solution to launch external apps from internal ones is given
* externalize Level app

firmware/application/CMakeLists.txt

@@ -293,7 +293,6 @@ set(CPPSRC
 	apps/ui_flash_utility.cpp
 	apps/ui_freqman.cpp
 	apps/ui_iq_trim.cpp
-	apps/ui_level.cpp
 	apps/ui_looking_glass_app.cpp
 	apps/ui_mictx.cpp
 	apps/ui_modemsetup.cpp
@@ -302,7 +301,6 @@ set(CPPSRC
 	apps/ui_rds.cpp
 	apps/ui_recon_settings.cpp
 	apps/ui_recon.cpp
-#	apps/ui_scanner.cpp
 	apps/ui_sd_over_usb.cpp
 	apps/ui_search.cpp
 	apps/ui_settings.cpp