Import libultraship as a submodule (#1943)

Co-authored-by: briaguya <briaguya>
Co-authored-by: Christopher Leggett <chris@leggett.dev>
Co-authored-by: David Chavez <davi@dcvz.io>

soh/src/code/audio_playback.c

@@ -1,5 +1,5 @@
 #include "global.h"
-#include <libultraship/Cvar.h>
+#include <Cvar.h>
 
 extern bool gUseLegacySD;
 

soh/src/code/audio_synthesis.c

@@ -1,6 +1,6 @@
 #include "ultra64.h"
 #include "global.h"
-#include <libultraship/mixer.h>
+#include <mixer.h>
 
 #define DEFAULT_LEN_1CH 0x1A0
 #define DEFAULT_LEN_2CH 0x340

soh/src/code/code_800F9280.c

@@ -1,7 +1,7 @@
 #include "ultra64.h"
 #include "global.h"
 #include <ultra64/abi.h>
-#include <libultraship/mixer.h>
+#include <mixer.h>
 
 typedef struct {
     u8 unk_0;

soh/src/code/main.c

@@ -3,7 +3,7 @@
 #include <soh/Enhancements/bootcommands.h>
 #include "soh/OTRGlobals.h"
 
-#include <libultraship/CrashHandler.h>
+#include <CrashHandler.h>
 #include "soh/CrashHandlerExp.h"
 
 

soh/src/code/z_play.c

@@ -4,7 +4,7 @@
 #include <string.h>
 
 #include "soh/Enhancements/gameconsole.h"
-#include <libultraship/ImGuiImpl.h>
+#include <ImGuiImpl.h>
 #include "soh/frame_interpolation.h"
 #include "soh/Enhancements/debugconsole.h"
 #include <overlays/actors/ovl_En_Niw/z_en_niw.h>