[mozjs68] Reorganize modules for ESM.
This merge request reorganizes the module file structure to support ESM. See #314 (moved)
Changes:
- Move the module gresource bundle to the project root.
- Move "script-based" modules into a separate sub-directory (script)
- Move shared code into a separate sub-directory (core)
When ESM is merged it will add a third directory (esm) for its code.
1 is necessary as ESM will also add JavaScript files in gjs/
which are run internally. We need the resource file to support the gjs/
path.
2 and 3 are necessary as both import systems are file-system based, and attempting to import each others' code should not be possible.