Remove the three item hamburger menu, re-distribute remaining items

There are only three, somewhat odd menu items remaining in this menu.
(Two if you don't have a camera.)

* Find your Friends, which is already accessible in a few other places
and currently has dubious utility.
* Create a Room, which also is barely used and can be combined with the
Create Space button in the space drawer.
* Scan a QR code, which can be placed in the account menu. I know this
isn't the most ideal place, but I can't think of anything better at the
moment.

src/rooms/RoomListPage.qml

@@ -270,9 +270,7 @@ Kirigami.Page {
     Component {
         id: exploreComponent
         ExploreComponent {
-            desiredWidth: root.width - Kirigami.Units.largeSpacing
             collapsed: root.collapsed
-            connection: root.connection
 
             onSearch: root.search()