[ADD][16.0] base_user_group_mgmt: manage groups/roles assignation with validation

[benwillig]

This PR creates two modules which allow users to assign group and roles to a user only if a workflow is approved.

• base_user_group_mgmt: add/remove groups from users, add/remove groups from groups
• base_user_group_mgmt_role: add/remove users from roles, add/removes groups from roles

Related fields are set readonly (only in the UI)

[github-actions[bot]]

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