Refactor js files (#48)

This pr is a significant reorg of the js files.

1) All non-basic functions have been moved out of the main glmv.js
2) 'Metadata' has been universally changed to mvconfig to avoid conflict with actual file metadata
3) Configuration changing functions have been split off into glmv-mvconfig.js
4) Hotspot modification functions have been split off into glmv-hs.js

Reviewed-on: #48

extension.json

@@ -72,7 +72,9 @@
                 "glmv-prev.css"
             ],
             "packageFiles": [
-                "glmv-prev.js"
+                "glmv-prev.js",
+                "glmv-mvconfig.js",
+                "glmv-hs.js"
             ]
         }
     }