[Docs] Creating a service account to call the API

[xgp]

add an API section to the Docs

https://github.com/keycloak/keycloak-documentation/blob/main/server_admin/topics/clients/oidc/service-accounts.adoc

https://www.keycloak.org/docs/latest/server_admin/index.html#_service_accounts

add the proper roles to give the service account user access to the resources you want to access.

On the client configuration page, under Service Account Roles, choose the Client Roles for “realm-management” and add the proper roles to you custom client.

Also make sure the mapper “roles” is added to your client scope.

[xgp]

TODO: make this a deployment default.

[xgp]

Example of how to use it: https://github.com/p2-inc/keycloak-events/issues/5