Update params and sample code in OAuth2.0

[izumo27]

• Add an explanation about the authorization server metadata path of OAuth2
  • [improve][client] Make authorization server metadata path configurable in AuthenticationOAuth2 pulsar#25052
• Update the sample code to use the builder
  • [feat][client] oauth2 trustcerts file and timeouts pulsar#24944
  • oauth2 authentication truststore and timeouts #1052

✅ Contribution Checklist

• I read the contribution guide
• I updated the versioned docs

[lhotari]

Thanks for the contribution!