support JWT / Oauth authorization headers pass to backend

[Slach]

https://gist.github.com/zvonand/54810e2c95c70b52b6e6f81cd54b44ce
https://grafana.com/blog/2024/07/31/an-overview-of-grafana-sso-benefits-recent-updates-and-best-practices-to-get-started/

https://grafana.com/developers/plugin-tools/how-to-guides/data-source-plugins/add-authentication-for-data-source-plugins#forward-oauth-identity-for-the-logged-in-user

https://www.slideshare.net/stormpath/rest-api-security-oauth-20-jwts-and-more
https://www.youtube.com/watch?v=NtAnyDJhkkg

[zvonand]

It is already supported -- Access token is passed in Authorization, id token is passed in X-Id-Token header

[Slach]

We wait when clickhouse-server will implement full OAuth without explicit user definition