Allow players to mute shellmap background music

mods/cnc/chrome/settings.yaml

@@ -311,6 +311,13 @@ Container@SETTINGS_PANEL:
 									Height: 20
 									Font: Regular
 									Text: Mute Sound
+								Checkbox@MUTE_BACKGROUND_MUSIC:
+									X: 15
+									Y: 103
+									Width: 200
+									Height: 20
+									Font: Regular
+									Text: Mute Background Music
 								Label@SOUND_LABEL:
 									X: PARENT_RIGHT - WIDTH - 270
 									Y: 40

mods/cnc/maps/blank-shellmap/map.yaml

@@ -32,4 +32,5 @@ Rules:
 		-CrateSpawner:
 		MusicPlaylist:
 			BackgroundMusic: map1
+			AllowMuteBackgroundMusic: true
 			DisableWorldSounds: true

mods/common/chrome/settings.yaml

@@ -322,6 +322,13 @@ Background@SETTINGS_PANEL:
 							Height: 20
 							Font: Regular
 							Text: Mute Sound
+						Checkbox@MUTE_BACKGROUND_MUSIC:
+							X: 15
+							Y: 103
+							Width: 200
+							Height: 20
+							Font: Regular
+							Text: Mute Background Music
 						Label@SOUND_LABEL:
 							X: PARENT_RIGHT - WIDTH - 270
 							Y: 40

mods/d2k/maps/shellmap/rules.yaml

@@ -13,6 +13,7 @@ World:
 		Maximum: 3
 	MusicPlaylist:
 		BackgroundMusic: options
+		AllowMuteBackgroundMusic: true
 		DisableWorldSounds: true
 	LuaScript:
 		Scripts: d2k-shellmap.lua

mods/ra/maps/desert-shellmap/rules.yaml

@@ -10,6 +10,7 @@ World:
 	-MPStartLocations:
 	MusicPlaylist:
 		BackgroundMusic: intro
+		AllowMuteBackgroundMusic: true
 		DisableWorldSounds: true
 	ResourceType@ore:
 		ValuePerUnit: 0

mods/ts/maps/fields-of-green/rules.yaml

@@ -13,6 +13,7 @@ World:
 	MusicPlaylist:
 		BackgroundMusic: intro
 		DisableWorldSounds: true
+		AllowMuteBackgroundMusic: true
 	GlobalLightingPaletteEffect:
 		Blue: 0.7
 		Ambient: 0.7