referrals: 1/2 generation routes, display route, partial frontend

route for generation/enabling of referral for user(s) done? the frontend
is mostly done, but functionality is not there yet. Route for finding
and displaying referral to user is done. Also the config option for
referral is there, in user page settings.

ts/typings/d.ts

@@ -40,6 +40,7 @@ declare interface Window {
     jellyfinLogin: boolean;
     jfAdminOnly: boolean;
     jfAllowAll: boolean;
+    referralsEnabled: boolean;
 }
 
 declare interface Update {
@@ -113,6 +114,7 @@ declare interface Modals {
     pwr?: Modal;
     logs: Modal;
     email?: Modal;
+    enableReferralsUser?: Modal;
 }
 
 interface Invite {