Add link to old UI to edit project access

If a user is an admin, show them the GWT link. If not an admin, don't
display.

Bug: Issue 7309
Change-Id: I63ce2e0ab22c68ebc6dbf0744fab06e9299329f3

polygerrit-ui/app/elements/admin/gr-project-access/gr-project-access.js

diff --git a/polygerrit-ui/app/elements/admin/gr-project-access/gr-project-access.js b/polygerrit-ui/app/elements/admin/gr-project-access/gr-project-access.js
index 8e1b1f5..470cf70 100644
--- a/polygerrit-ui/app/elements/admin/gr-project-access/gr-project-access.js
+++ b/polygerrit-ui/app/elements/admin/gr-project-access/gr-project-access.js
@@ -22,7 +22,13 @@
         type: String,
         observer: '_projectChanged',
       },
+      // The current path
+      path: String,
 
+      _isAdmin: {
+        type: Boolean,
+        value: false,
+      },
       _capabilities: Object,
       _groups: Object,
       /** @type {?} */
@@ -67,6 +73,10 @@
         return res.labels;
       }));
 
+      promises.push(this.$.restAPI.getIsAdmin().then(isAdmin => {
+        this._isAdmin = isAdmin;
+      }));
+
       return Promise.all(promises).then(value => {
         this._capabilities = value[1];
         this._labels = value[2];
@@ -79,6 +89,10 @@
       });
     },
 
+    _computeAdminClass(isAdmin) {
+      return isAdmin ? 'admin' : '';
+    },
+
     _computeParentHref(projectName) {
       return this.getBaseUrl() +
           `/admin/projects/${this.encodeURL(projectName, true)},access`;