Adding exitUrl property

The exitUrl property can be applied on a layer to link to any kind of room (private or public)

front/src/Connexion/Room.ts

@@ -6,8 +6,10 @@ export class Room {
     public readonly isPublic: boolean;
     private mapUrl: string|undefined;
     private instance: string|undefined;
+    public readonly hash: string;
 
     constructor(id: string) {
+        this.hash = '';
         if (id.startsWith('/')) {
             id = id.substr(1);
         }
@@ -19,6 +21,13 @@ export class Room {
         } else {
             throw new Error('Invalid room ID');
         }
+
+        const indexOfHash = this.id.indexOf('#');
+        if (indexOfHash !== -1) {
+            const idWithHash = this.id;
+            this.id = this.id.substr(0, indexOfHash);
+            this.hash = idWithHash.substr(indexOfHash + 1);
+        }
     }
 
     public async getMapUrl(): Promise<string> {