Get commentlinks per-project in UI code

Remove commentlinks from GerritConfig and instead provide them in JSON
form from GET /projects/X/config. On the client side, create new
CommentLinkProcessor instances when loading a change or patch.
Fortunately, even though this requires another RPC to get the project
config, in all existing screen instances, there is already an RPC we
can parallelize it with.

In the long term we may want to enable server-side HTML rendering, but
that requires enabling this option on a variety of RPC endpoints, not
all of which are converted to the new REST API. In addition, there is
the problem of defining a stable HTML fragment style. For example, the
commit message template is currently implemented using a
not-quite-trivial template in GWT's UiBinder, so some of that
formatting and styling would need to be hoisted out into the server
side; doable, but we're not there yet.

Change-Id: Iaecbeff939c8fcbc1c6f500e0b04ce03f35e1fd3

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeDescriptionBlock.java

@@ -14,6 +14,7 @@
 
 package com.google.gerrit.client.changes;
 
+import com.google.gerrit.client.ui.CommentLinkProcessor;
 import com.google.gerrit.common.data.AccountInfoCache;
 import com.google.gerrit.common.data.SubmitTypeRecord;
 import com.google.gerrit.reviewdb.client.Change;
@@ -37,10 +38,11 @@ public class ChangeDescriptionBlock extends Composite {
   }
 
   public void display(Change chg, Boolean starred, Boolean canEditCommitMessage,
-      PatchSetInfo info,
-      final AccountInfoCache acc, SubmitTypeRecord submitTypeRecord) {
+      PatchSetInfo info, AccountInfoCache acc,
+      SubmitTypeRecord submitTypeRecord,
+      CommentLinkProcessor commentLinkProcessor) {
     infoBlock.display(chg, acc, submitTypeRecord);
     messageBlock.display(chg.currentPatchSetId(), starred,
-      canEditCommitMessage,  info.getMessage());
+        canEditCommitMessage, info.getMessage(), commentLinkProcessor);
   }
 }