Determine correct location and Lint configuration for third-party plugin mobile JS

The Moodle Mobile app allows third-party plugins to write JS for their own code.

Right now we do not require tht all JS be in a specific location which means it is dotted in random places within the plugin. This means that it is impossible to apply relevant linting rules and sanity checks to it.

We should determine a place for all JS code to be placed, document it, and apply appropriate eslint configuration for that location.

We should also update the moodle-local_ci plugin and smurf checks to show any JS outside of standard locations for Moodle (amd/src, amd/build, yui, [this new location], module.js).