Move CommentInfo and subtypes to public API

Internal types import them from public API and re-export them.

Derived types like Comment and CommentThread will be considered next,
but they are not part of the REST API directly.

Release-Notes: skip
Change-Id: If97c2c36b9a67550318a877f11b10e18179bd2f1
diff --git a/polygerrit-ui/app/constants/constants.ts b/polygerrit-ui/app/constants/constants.ts
index b9ed56b..25d25b0 100644
--- a/polygerrit-ui/app/constants/constants.ts
+++ b/polygerrit-ui/app/constants/constants.ts
@@ -13,6 +13,7 @@
 import {
   AuthType,
   ChangeStatus,
+  CommentSide,
   ConfigParameterInfoType,
   DefaultDisplayNameConfig,
   EditableAccountField,
@@ -32,6 +33,7 @@
 export {
   AuthType,
   ChangeStatus,
+  CommentSide,
   ConfigParameterInfoType,
   DefaultDisplayNameConfig,
   EditableAccountField,
@@ -160,15 +162,6 @@
 }
 
 /**
- * The side on which the comment was added
- * https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#comment-info
- */
-export enum CommentSide {
-  REVISION = 'REVISION',
-  PARENT = 'PARENT',
-}
-
-/**
  * Allowed app themes
  * https://gerrit-review.googlesource.com/Documentation/rest-api-accounts.html#preferences-input
  */