feat: initial admin PAT has IAM_LOGIN_CLIENT (#10143)

# Which Problems Are Solved

We provide a seamless way to initialize Zitadel and the login together.

# How the Problems Are Solved

Additionally to the `IAM_OWNER` role, a set up admin user also gets the
`IAM_LOGIN_CLIENT` role if it is a machine user with a PAT.

# Additional Changes

- Simplifies the load balancing example, as the intermediate
configuration step is not needed anymore.

# Additional Context

- Depends on #10116 
- Contributes to https://github.com/zitadel/zitadel-charts/issues/332
- Contributes to https://github.com/zitadel/zitadel/issues/10016

---------

Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>

cmd/setup/steps.yaml

@@ -6,6 +6,7 @@ FirstInstance:
   MachineKeyPath: # ZITADEL_FIRSTINSTANCE_MACHINEKEYPATH
   # The personal access token from the section FirstInstance.Org.Machine.Pat is written to the PatPath.
   PatPath: # ZITADEL_FIRSTINSTANCE_PATPATH
+  LoginClientPatPath: # ZITADEL_FIRSTINSTANCE_LOGINCLIENTPATPATH
   InstanceName: ZITADEL # ZITADEL_FIRSTINSTANCE_INSTANCENAME
   DefaultLanguage: en # ZITADEL_FIRSTINSTANCE_DEFAULTLANGUAGE
   Org:
@@ -46,6 +47,13 @@ FirstInstance:
       Pat:
         # date format: 2023-01-01T00:00:00Z
         ExpirationDate: # ZITADEL_FIRSTINSTANCE_ORG_MACHINE_PAT_EXPIRATIONDATE
+    LoginClient:
+      Machine:
+        Username: # ZITADEL_FIRSTINSTANCE_ORG_LOGINCLIENT_MACHINE_USERNAME
+        Name: # ZITADEL_FIRSTINSTANCE_ORG_LOGINCLIENT_MACHINE_NAME
+      Pat:
+        # date format: 2023-01-01T00:00:00Z
+        ExpirationDate: # ZITADEL_FIRSTINSTANCE_ORG_LOGINCLIENT_PAT_EXPIRATIONDATE
 
 CorrectCreationDate:
   FailAfter: 5m # ZITADEL_CORRECTCREATIONDATE_FAILAFTER