BE: AUth: Implement JWT auth w/ JWKS

[Haarolean]

https://docs.spring.io/spring-security/reference/servlet/oauth2/resource-server/jwt.html

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via: https://github.com/provectus/kafka-ui/issues/4145

In our case we have a central place where authentication already happens using Azure AD as IDP, and we would like to just forward the JWT resultant from the oauth provider authentication to kafka-ui, and then kafka-ui could just validate the jwt using JWKS (https://auth0.com/docs/secure/tokens/json-web-tokens/json-web-key-sets).

A similar feature is present in Grafana (https://grafana.com/docs/grafana/latest/setup-grafana/configure-security/configure-authentication/jwt/#verify-token-using-a-json-web-key-set-loaded-from-https-endpoint), which we are using fine.

As it is now, our only solution is to authenticate using Azure AD in our central place to get access to the internal network to reach kafka-ui, and then authenticate again into kafka-ui using the same method.