No theme and default BG and patch BG bug when hitting F11 (#1070)

* Add setting slot for no theme & default BG

* Whitelist 4 seasons theme + blocking console's theme command if theme disabled

* Small update theme.lua

* Expose the WIDGET.setOnChange() to use in setting_video.lua

* Shorten "Use custom B.G." to "Custom B.G."

* Shorten theme code, and edit the UI

* Add lock BG

* Add VI translation

* Fullscreen patch

* Modify UI

* Small change

* Undo a mistake

parts/gameTables.lua

@@ -659,6 +659,9 @@ do-- Userdata tables
         msaa=0,
         bg='on',
         bgAlpha=.26,
+        defaultBG='space',
+        lockBG=false,
+        noTheme=false,
         powerInfo=false,
         clickFX=true,
         warn=true,