Add oidc-client authorization provider

[ngbrown]

I saw that you were open to other identity providers besides Auth0, so how about oidc-client?

[ngbrown]

I've created a version that supports oidc-client and Identity Server here: https://gist.github.com/ngbrown/0be839b1f56679e6d41bbe5f36538931

I started with a very similar API, except that the isAuthenticated is directly from the state and updated on expire instead of being a function. With the way this repository exposes isAuthenticated as a function, doesn't correctly let the components know when to re-render.

Use as inspiration if you want.