Add a server config for disabling robot comments in the UI

We are planning to deprecate robot comments. So this is a setting for
hosts to opt-in early into turning robot comments off.

The UI will not show a `Findings` tab and will not even try to load
robot comments, if this config value is set to `false`.

Release-Notes: skip
Google-Bug-Id: b/227463363
Change-Id: Iddbcfb38b023055a02804653ad72fc17aca5ecf4
diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 19445b8..464c59b 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -1537,6 +1537,13 @@
 +
 By default true.
 
+[[change.enableRobotComments]]change.enableRobotComments::
++
+Are robot comments enabled in the Gerrit UI? This setting allows phasing out
+robot comments.
++
+By default true.
+
 [[change.robotCommentSizeLimit]]change.robotCommentSizeLimit::
 +
 Maximum allowed size in characters of a robot comment. Robot comments which