Request to add e2e test scenarios

[yanmxa]

Scenarios:

1. Delete the MGH CR and verify the global hub finalizer is removed from managed clusters. ref: Remove the global hub finalizer from managed cluster when deleting the MGH CR #320
2. Delete the MGH CR and create a new one with transportFormat: message, then verify that the policy and application can work properly.
3. Set up hosted mode environment for the global hub by adding setup scripts.
4. In hosted mode, create a serviceaccount and bind it with the clusterrole cluster-admin, then verify the token of the account can access the global hub API.
5. In hosted mode, create an inform policy and then change it to enforce, verify the policy status is updating from non-compliant to compliant.
6. In hosted mode, create an application and verify the application is propagated to the managed cluster.
7. In hosted mode, delete the MGH CR and verify the global hub finalizer is removed from policy, appsub, placements, etc.
8. Verify resources with the label global-hub.open-cluster-management.io/local-resource, it won't be transferred to the regional hub clusters.
9. Using Placement API to schedule policy.