Snake (#2549)

* Create the Shopping Cart Lock app

Will demonstrate tomorrow. Don't merge until I do 😁

* Fixes for HTotoo's comments 😎

* Improved audio the best I can.

If nobody has any ideas to further improve high frequencies of the audio, the hardware may not be capable. I still need to check with line-out to better speaker to make sure it's not just the speaker, but it shouldn't be.

* Compared against baseband_api.cpp - matched some things better but still playback seems to be missing higher fq sounds

* renamed wav files to a more specific / less generic name

* indentation + using variables instead of litteral names for wav files to use

* indentation

* Made a Snake game - enjoy

* Code formatting. I always forget.

* move to keep sort order

* Update external.ld

Sorry I should have also asked if there was any reason that address ranges 0xADDA0000--0xADDD0000 were skipped in external.ld.  I assumed there wasn't so I changed it to be consecutive using the same 0x10000 step as the other modules.  If there is any reason to skip them then we should add a comment to note it.  Of course these are all just temporary address values used for linking and get overwritten by a kludgy "search & replace" during the build process.

Resolves enhancement request #764

---------

Co-authored-by: gullradriel <gullradriel@no-mail.com>
Co-authored-by: Mark Thompson <129641948+NotherNgineer@users.noreply.github.com>

firmware/application/external/external.cmake

@@ -4,10 +4,14 @@ set(EXTCPPSRC
 	external/tetris/main.cpp
 	external/tetris/ui_tetris.cpp
 
-	#tetris
+	#breakout
 	external/breakout/main.cpp
 	external/breakout/ui_breakout.cpp
 
+	#snake
+	external/snake/main.cpp
+	external/snake/ui_snake.cpp
+
 	#afsk_rx
 	external/afsk_rx/main.cpp
 	external/afsk_rx/ui_afsk_rx.cpp
@@ -192,6 +196,7 @@ set(EXTAPPLIST
 	keyfob
 	tetris
 	breakout
+	snake
 	extsensors
 	foxhunt_rx
 	audio_test