Changes at "Management the registrations and deregistretion participants of an instance"

**Is your feature request related to a problem? Please describe.**\nFor the case of organizations it's needed the possibility to management the ups and downs of the members of an organization, Usually the membership is related to pay a share. Actually it's not possible to delete participants of an instance. We received so many claims in this sense. \n\n**Describe the solution you'd like**\nThe possibility to delete participants of an instance from the Admin dashboard. We should discuss how this could be done and who could have the permisions to do it. Maybe could be a group of people? Maybe we could allowed the deleted participant to claim?\n\n**Describe alternatives you've considered**\nThe private participants it's a temporary solution to this, but it's not confortable for some organizations. \n\n**Additional context**\n\n\n**Does this issue could impact on users private data?**\nYes