feat: enforce user roles

enforces user admin role requirement for
- creating / deleting / setting role for organization users
- creating / deleting / setting role for project users
- updating project name
- deleting project

hides action elements based on role for
- admin console
- team settings if team is only visible through project membership
- add project tile if not team admin
- project name text editor if not team / project admin
- add redirect from team page if settings only visible through project
  membership
- add redirect from admin console if not org admin

role enforcement is handled on the api side through a custom GraphQL
directive `hasRole`. on the client side, role information is fetched in
the TopNavbar's `me` query and stored in the `UserContext`.

there is a custom hook, `useCurrentUser`, that provides a user object
with two functions, `isVisibile` & `isAdmin` which is used to check
roles in order to render/hide relevant UI elements.

frontend/src/shared/components/Admin/Admin.stories.tsx

@@ -25,6 +25,7 @@ export const Default = () => {
       <ThemeProvider theme={theme}>
         <Admin
           onInviteUser={action('invite user')}
+          canInviteUser
           initialTab={1}
           onUpdateUserPassword={action('update user password')}
           onDeleteUser={action('delete user')}