Set community settings to JSONB + add tests for settings and avatar_url

tests/api_tests/hivemind/tavern/bridge_api_patterns/get_community/hive-135485.pat.json

 {
   "about": "A place for major news from around the world.",
-  "avatar_url": "",
+  "avatar_url": "http://example.com",
   "context": {},
   "created_at": "2016-09-15 18:01:30",
   "description": "",
   "flag_text": "",
-  "id": 92457,
+  "id": 92458,
   "is_nsfw": true,
   "lang": "en",
   "name": "hive-135485",
   "num_authors": 5,
   "num_pending": 28,
-  "settings": {},
+  "settings": {
+    "avatar_url": "http://example.com",
+    "emotes": {},
+    "streams": [
+      [
+        "Say It Here",
+        "0",
+        [
+          "member"
+        ],
+        [
+          "member"
+        ]
+      ],
+      [
+        "About",
+        "/about",
+        null,
+        null
+      ],
+      [
+        "Visit Community",
+        "/created",
+        null,
+        null
+      ]
+    ]
+  },
   "subscribers": 4,
   "sum_pending": 0,
   "team": [
@@ -33,4 +60,4 @@
   ],
   "title": "World News",
   "type_id": 1
-}
+}
\ No newline at end of file