feat: move to advanced plugin and add reset API

[wseymour15]

Description

This will be a breaking change, and we will need this to be a major version bump
Since the user will no longer be able to reset the options with the player.overlay() functionality after moving to an advanced plugin, we now have the overlay.reset() function to do something similar.

These changes move the plugin from a function to an advanced plugin, giving the plugin lifecycle methods.

Specific Changes proposed

• Move the plugin from a function to and advanced plugin class
• Add a reset function to update the plugin options and reset the overlays.
• Add an additional bundled file videojs-overlay.plugin.js to the dist so we have a way of importing this plugin class without registering/initializing it.

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Unit Tests updated or fixed
  • Docs/guides updated
• Reviewed by Two Core Contributors

[dzianis-dashkevich]

I would assume we want this to be initialized in the index file, not here

[wseymour15]

That's fair. I guess we will still need a way to call initOverlayComponent in the plugin only scenario, so I also made a change to export that along with the plugin in the plugin-only bundle.