Add Administration, starting with accounts

An account whose Stalwart role manages accounts now finds Administration in
the account menu. It lists, searches, creates and edits accounts -- display
name, other addresses, role, storage limit -- sets a new password, and
deletes, each offered only when the role holds the matching permission.

The server keeps the permissions list from GET /api/account, which it
already called for the edition and threw the rest away. Everything else is
JMAP x:Account, x:Domain and x:Role calls through the existing /api/jmap
proxy, so nothing new is stored and Stalwart decides every call.

Stalwart checks a grant against the caller's permissions but not a password
change or a delete, so an account that outranks the viewer is shown
read-only. Your own password is changed in Settings, which re-seals the
session; changing it here would strand it.

The mock server gains a directory behind the same permission names, with
MOCK_ROLE choosing admin, tenant-admin, helpdesk or user.

68 new strings, translated in all nine catalogues; strings falling back to
English stay at 16.

web/src/App.tsx

@@ -31,6 +31,8 @@ const ContactsView = lazy(() => import("@/views/contacts/ContactsView").then((m)
 const CalendarView = lazy(() => import("@/views/calendar/CalendarView").then((m) => ({ default: m.CalendarView })));
 const FilesView = lazy(() => import("@/views/files/FilesView").then((m) => ({ default: m.FilesView })));
 const SettingsView = lazy(() => import("@/views/settings/SettingsView").then((m) => ({ default: m.SettingsView })));
+// Only ever opened by the few who administer, so nobody else downloads it.
+const AdminView = lazy(() => import("@/views/admin/AdminView").then((m) => ({ default: m.AdminView })));
 
 export function App() {
   const status = useSession((s) => s.status);
@@ -305,6 +307,7 @@ function AuthedApp() {
           <Route path="/calendar/:view?/:date?">{(p) => <CalendarView view={p.view} date={p.date} />}</Route>
           <Route path="/files/:nodeId?">{(p) => <FilesView nodeId={p.nodeId} />}</Route>
           <Route path="/settings/:section?">{(p) => <SettingsView section={p.section} />}</Route>
+          <Route path="/admin/:section?/:id?">{(p) => <AdminView section={p.section} id={p.id} />}</Route>
           <Route path="/login">
             <Redirect to="/mail" />
           </Route>