Add ability to delete Maybe account (#698)

* Build out user deactivation and purging workflows

* Add i18n translations for user deletion

* Add tests for user deletion

* Fix lint issue

test/fixtures/users.yml

@@ -4,6 +4,7 @@ family_admin:
   last_name: Dylan
   email: bob@bobdylan.com
   password_digest: <%= BCrypt::Password.create('password') %>
+  role: admin
 
 family_member:
   family: dylan_family