Allow adding Media Element plugins?

[timstallmann]

Hi! I'm using this plugin on an Omeka site where we'd like to add some additional Media Element plugins. I've managed to make this work on my end by:

• Adding the plugin CSS & JS in my own custom Omeka plugin via hook_public_head and hook_admin_head.
• Extending Html5Media plugin to add an extra Custom mediaplayer settings config option which passes text into the JS configuration object for the mediaplayer element.

I'd love to submit a PR for some of this functionality but wondering what the best approach would be? I could just submit a PR for the Custom mediaplayer settings` config option, but I wonder if it might be more usable for less tech-savvy folks to add a "Media Player plugins" config section where users could toggle on and off different plugins?

Look forward to hearing your thoughts!