feat: implement space hierarchy

- implement spaces hierarchy
- create expandable navigation drawer tiles
- display suggested rooms below joined rooms when in space
- everything works nested
- fix shared preferenced conflic with debug builds on Linux
- add [`package:async`](https://pub.dev/packages/async)

Signed-off-by: TheOneWithTheBraid <the-one@with-the-braid.cf>

assets/l10n/intl_en.arb

@@ -174,6 +174,13 @@
     "type": "text",
     "placeholders": {}
   },
+  "numberRoomMembers": "{number} members",
+  "@numberRoomMembers": {
+    "type": "number",
+    "placeholders": {
+      "number": {}
+    }
+  },
   "badServerLoginTypesException": "The homeserver supports the login types:\n{serverVersions}\nBut this app supports only:\n{supportedVersions}",
   "@badServerLoginTypesException": {
     "type": "text",
@@ -210,6 +217,7 @@
       "targetName": {}
     }
   },
+  "suggestedRooms": "Discover groups in this space",
   "blockDevice": "Block Device",
   "@blockDevice": {
     "type": "text",