Deprecate auth_oauth2.jwks_url and its corresponding erlang config entry

[MarcialRosales]

Is your feature request related to a problem? Please describe.

auth_oauth2.jwks_url is the configuration variable that configures the JSON Web Key Sets endpoint.

When RabbitMQ introduced support for multiple oauth providers, auth_oauth2.oauth_providers.$name.jwks_uri was used instead. jwks_uri is the actual endpoint name used by OpenId Discovery Endpoint and RabbitMQ uses that endpoint to download all the other endpoints including the jwks_uri.
A user may choose to configure the issuer url on a given oauth provider, e.g. auth_oauth2.oauth_providers.okta.issuer or instead configure the individual endpoints' urls, .e.g auth_oauth2.oauth_providers.okta.jwks_uri = https://someurl.

Describe the solution you'd like

It can be very confusing having jwks_uri and jwks_url in the OAuth2 configuration.

For this reason, RabbitMQ is deprecating auth_oauth2.jwks_url in favour of auth_oauth2.jwks_uri.

Describe alternatives you've considered

No response

Additional context

No response

[MarcialRosales]

Implemented on #12399