adds some siteConfig settings for future use

cli/defaults/siteConfig.json

@@ -23,6 +23,7 @@
   "publishing": {
     "primaryClaimAddress": null,
     "uploadDirectory": "/home/lbry/Uploads",
+    "lbrynetHome": "/home/lbry",
     "thumbnailChannel": null,
     "thumbnailChannelId": null,
     "additionalClaimAddresses": [],
@@ -39,6 +40,18 @@
     "maxSizeGif": 50000000,
     "maxSizeVideo": 50000000
   },
+  "serving": {
+    "markdownSettings": {
+      "skipHtml": true,
+      "privilegedDisallowedTypesDescriptions": ["Image"],
+      "privilegedDisallowedTypesMain": [],
+      "publicDisallowedTypesDescriptions": ["Image"],
+      "publicDisallowedTypesMain": []
+    },
+    "customFileExtensions": {
+      "application/example-type": "example"
+    }
+  },
   "startup": {
     "performChecks": true,
     "performUpdates": true