[REF] mgmtsystem_action

The current module inherit `crm.claim` while the `state` attribute doesn't exist anymore. I made some changes to use the `stage_id` instead but I'm not so sure it's a good idea. I'm open to suggestions.
State was removed remember.
It's best to remove the methods to change state (and corresponding form buttons.)
That's what Odoo did in similar models, such as "Project Issues".