Add your favourite oauth2/oidc provider config

Currently we ship automatic config for several providers, however this is a very short list:

https://github.com/vert-x3/vertx-auth/blob/master/vertx-auth-oauth2/src/main/java/io/vertx/ext/auth/oauth2/providers/

This task, is about adding config for other providers, for example:

* apple
* attlassian
* auth0
* battlenet
* discord
* ~gitlab~
* identity-server4
* okta
* twitch
* spotify
* yandex
* etc...

The task is about cloning one of the existing providers, for example the github provider:

https://github.com/vert-x3/vertx-auth/blob/master/vertx-auth-oauth2/src/main/java/io/vertx/ext/auth/oauth2/providers/GithubAuth.java

And fill the right values for the provider:

https://github.com/vert-x3/vertx-auth/blob/master/vertx-auth-oauth2/src/main/java/io/vertx/ext/auth/oauth2/providers/GithubAuth.java#L55-L64

The config should be annotated with code comments where the information was found, in order to be fully accepted. For example, when working with GitHub the code should include a comment that the API documentation currently lives in: https://docs.github.com/en/developers/apps/authorizing-oauth-apps so reviewers can verify the code.

Bonus points if you also document the `userInfo` endpoint with which fields are returned as it would be useful for: #405