UAA should publish Authorization Server Metadata, RFC 8414

[strehle]

UAA acts as OAuth2 authorization server and OIDC one.
For OIDC we publish well-knonw -> UAA/.well-known/openid-configuration

But UAA should also publish "/.well-known/oauth-authorization-server"

https://datatracker.ietf.org/doc/html/rfc8414

[strehle]

@Kehrlann FYI , wdyt ?

[Kehrlann]

@strehle Unless our customers require it, I don't think this is high priority:

• Spring uses it as a backup if openid-configuration is not available
• Some major players do not publish it, they only publish openid-configuration (e.g. Microsoft and Google do not publish it, only openid-configuration)

Since we already have oidc, it should be good enough in most use-cases.