chore: rename testadmin and testuser to admin and user for simplicity

Signed-off-by: Bert-Jan Fikse <bert-jan@whatwedo.ch>

inventories/vagrant/host_vars/backend/keycloak.yml

@@ -17,14 +17,14 @@ keycloak_groups:
 
 # Local users to provision
 keycloak_local_users:
-  - username: testadmin
+  - username: admin
     first_name: "Test"
     last_name: "Admin"
     email: "admin@local.test"
     password: "admin"
     groups:
       - name: admins
-  - username: testuser
+  - username: user
     first_name: "Test"
     last_name: "User"
     email: "user@local.test"