move wellKnownJson to domains

after some more thought:
* If app moves to another location, user has to remember to move all this config
* It's not really associated with an app. It's to do with the domain info
* We can put some hints in the UI if app is missing.

part of #703

src/test/apps-test.js

@@ -83,7 +83,8 @@ describe('Apps', function () {
         provider: 'noop',
         config: { },
         fallbackCertificate: null,
-        tlsConfig: { provider: 'fallback' }
+        tlsConfig: { provider: 'fallback' },
+        wellKnown: null
     };
 
     const DOMAIN_1 = {
@@ -92,7 +93,8 @@ describe('Apps', function () {
         provider: 'noop',
         config: { },
         fallbackCertificate: null,
-        tlsConfig: { provider: 'fallback' }
+        tlsConfig: { provider: 'fallback' },
+        wellKnown: null
     };
 
     var APP_0 = {