Add gr-account-list

This new element is a more general variation of gr-reviewer-list.
The user can enter additions, which are staged in the list with
a distinct style and are removable. These pending additions can
then be committed later in response to some other user action.

Change-Id: I043665b572606d8e49b97aeaee9740a1236cd923
diff --git a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.html b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.html
index b7f9715..f136907 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.html
+++ b/polygerrit-ui/app/elements/shared/gr-account-label/gr-account-label.html
@@ -23,6 +23,9 @@
       :host {
         display: inline;
       }
+      :host::after {
+        content: var(--account-label-suffix);
+      }
       gr-avatar {
         height: 1.3em;
         width: 1.3em;