Module Files: Serve from the Library not the file system

[dasgarner]

When creating a custom module, if it uses any resources these also have to be in /web/modules. This isn't optimal when using Docker as you have to mount those resources into the container using a volume.

This needs to be improved so that those resources are served from the Library directly - in the same way that they are for the Player.

We should change getResourceUrl so that - for preview - it looks up the resource provided and gives a download link that serves the file from the library instead.

[dasgarner]

Something like this might be suitable:

//to get the id automatically
if ($isPreview) {
    $media = $this->mediaFactory->getByName('name');
    $url = $this->getApp()->urlFor('library.download', ['id' => $media->mediaId]);
} else {
    $url = $this->getResourceUrl('your file name');
}
// use the $url here

[dasgarner]

We'd have to ensure that the permission checking in library download didn't get in the way of serving these files.

I think this just needs to be that module system files are downloadable by all.