feat(grafana): authorization by group membership

[v-rocheleau]

Keycloak users can only signin to Grafana if they belong to a Grafana group with valid permissions in Keycloak.
Roles are as follow:

• viewer: user can view dashboards
• editor: user can create dashboards and explore the data
• admin: user can manage users.

Grafana expects one of these roles to be present in the ID token when authenticating, otherwise the user is blocked.

Use bentoctl init-auth with the monitoring feature flag to create the Grafana client, it's roles, groups and mappers.

Also added the Grafana and Loki directories to bentoctl init-dirs.

[davidlougheed]

reconcile with releases/v17 to add client creation helper + verbose argument(?)

[davidlougheed]

Lgtm