[feature] Allow non superadmin to create, manage and own org

[nemesifier]

If a staff user which is not superadmin has permission to create/change/delete organizations, we must make sure that when this user creates an organization, their account is flagged as owner and automatically associated to this org as manager (OrganizationUser(is_admin=True)).

[himanshu-sharmav]

@nemesifier I would like to work on this issue.

[nemesifier]

@himanshu-sharmav please select an easier issue to start contributing, there's plenty of more entry level issues. Leave this for more experienced contributors, thanks.