embyupdate: Allow direct configuration of user ID for private users

[JoshDi]

In the embyupdate.py plugin, if the admin user listed in the beets config is hidden from login screens, the embyupdate plugin will fail and not find the username.

I am using an API key, which is server wide so the username does not really matter. Therefore the get_user function should just return the user provided in the beets config

We should also allow for the emby user ID (string/hash) to be supplied directly from the beets config to avoid this situation.

can this change be made please?

[sampsyo]

Sounds very reasonable! Any chance you could try putting together a PR to show how this would work?

[shoriminimoe]

I happened to encounter this recently. I'm happy to submit a PR for this.