fix(appservices): don't panic on empty registration url

perf(appservices): cache regex for namespaces

src/service/mod.rs

@@ -4,7 +4,7 @@ use std::{
 };
 
 use lru_cache::LruCache;
-use tokio::sync::Mutex;
+use tokio::sync::{Mutex, RwLock};
 
 use crate::{Config, Result};
 
@@ -56,7 +56,10 @@ impl Services {
         config: Config,
     ) -> Result<Self> {
         Ok(Self {
-            appservice: appservice::Service { db },
+            appservice: appservice::Service {
+                db,
+                registration_info: RwLock::new(HashMap::new()),
+            },
             pusher: pusher::Service { db },
             rooms: rooms::Service {
                 alias: rooms::alias::Service { db },