Removing an account (#660) drops its team memberships. If it was the only member of an organization's Owners team, the organization is left with nobody who can administer it: its repositories, teams and settings become unreachable.
Acceptance criteria
[ ] Removing an account that is the last owner of an organization is refused unless the admin names who takes the organization over (another member), or chooses to remove the organization and its repositories with it, after a confirm page that lists them.
[ ] The accounts page shows which organizations an account is the only owner of.
[ ] Test: removing a sole org owner without a successor is refused and changes nothing; with a successor the organization keeps an owner.
Removing an account (#660) drops its team memberships. If it was the only member of an organization's Owners team, the organization is left with nobody who can administer it: its repositories, teams and settings become unreachable.
Acceptance criteria