gitadora: option for guitar picking algorithm (#528)

## Link to GitHub Issue, if one exists
n/a

## Description of change
Adds an option to pick from four algorithms for guitar picking input.

The default behavior is being switched from legacy (rising edge only,
always 1 frame of input) to SOCD "prefer recent" algorithm. This makes
it slightly easier to navigate the menu with the guitar.

## Testing
Validated gw, gwdelta, and sdvx just in case.

src/spice2x/games/gitadora/gitadora.h

@@ -4,6 +4,7 @@
 
 #include "avs/game.h"
 #include "games/game.h"
+#include "util/socd_cleaner.h"
 
 namespace games::gitadora {
 
@@ -14,6 +15,7 @@ namespace games::gitadora {
     extern bool P1_LEFTY;
     extern bool P2_LEFTY;
     extern std::optional<std::string> SUBSCREEN_OVERLAY_SIZE;
+    extern std::optional<socd::SocdAlgorithm> PICK_ALGO;
 
     class GitaDoraGame : public games::Game {
     public: