Chore: Adding "allowed_groups" Configuration Parameter to Generic OAuth Method (#69025)

* feat: add allowed_groups for Generic OAuth

* docs: add allowed_groups more docs for Generic OAuth

docs/sources/setup-grafana/configure-security/configure-authentication/generic-oauth/index.md

@@ -45,6 +45,7 @@ auth_url =
 token_url =
 api_url =
 allowed_domains = mycompany.com mycompany.org
+allowed_groups = ["Admins", "Software Engineers"]
 tls_skip_verify_insecure = false
 tls_client_cert =
 tls_client_key =
@@ -85,6 +86,8 @@ Similarly, group mappings are made using [JMESPath](http://jmespath.org/examples
 
 Furthermore, Grafana will check for the presence of at least one of the teams specified via the `team_ids` configuration option using the [JMESPath](http://jmespath.org/examples.html) specified via the `team_ids_attribute_path` configuration option. The JSON used for the path lookup is the HTTP response obtained from querying the Teams endpoint specified via the `teams_url` configuration option (using `/teams` as a fallback endpoint). The result should be a string array of Grafana Team IDs. Using this setting ensures that only certain teams is allowed to authenticate to Grafana using your OAuth provider.
 
+You can limit access to only members of a given group or list of groups by setting the `allowed_groups` option.
+
 ### Login
 
 Customize user login using `login_attribute_path` configuration option. Order of operations is as follows: