[UI] Custom global role creation

[rmweir]

What kind of request is this (question/bug/enhancement/feature request):
enhancement

What:
UI for a admin to create custom global role and set it as default. Admin should be able to clone existing global role.

Backend Issue:
#16216

[tfiduccia]

UI - Will be same as it is for Cluster and Projects.

1. Add button to top of Global role list that says "Add Global Role"
   
2. Click on button and there it should match Project & Cluster Add pages:
   

[westlywright]

Updates to the requirements for global roles:

1. Locked is not a concept that exists on a global role so it will not be displayed in the UI.
2. Inheritance isn't a concept that is applied to global roles as well so it is not displayed in the UI.

[jiaqiluo]

The feature is validated in master-head 5845c2d

• Admin can add a custom global role
• Admin can clone existing global roles

the global role page:

adding/cloning a role:

the role shows in the list:

More tests will be done and bugs will be tracked by independent issues.