[ACS-4537] Make aca-about secondary entry of aca-content (#3179)

* break dependency on core module

* convert about to secondary entry

* Fixes after rebase

* [ACS-4537] - Copy about assets

---------

Co-authored-by: Denys Vuika <denys.vuika@gmail.com>

projects/aca-content/about/assets/about.plugin.json

@@ -0,0 +1,45 @@
+{
+  "$schema": "../../../../extension.schema.json",
+  "$id": "14157f82-6489-4187-9b68-1a5e38fadeca",
+  "$name": "About Plugin",
+  "$version": "0.0.1",
+  "$vendor": "Hyland Software, Inc. and its affiliates",
+  "$license": "LGPL-3.0",
+
+  "actions": [
+    {
+      "id": "app.actions.about",
+      "type": "NAVIGATE_URL",
+      "payload": "/about"
+    }
+  ],
+
+  "routes": [
+    {
+      "id": "app.about",
+      "path": "about",
+      "layout": "app.layout.main",
+      "component": "app.about.component"
+    }
+  ],
+
+  "features": {
+    "header": [
+      {
+        "id": "app.header.more",
+        "children": [
+          {
+            "id": "app.header.about",
+            "order": 100,
+            "title": "APP.BROWSE.ABOUT.TITLE",
+            "description": "APP.BROWSE.ABOUT.TITLE",
+            "icon": "info",
+            "actions": {
+              "click": "app.actions.about"
+            }
+          }
+        ]
+      }
+    ]
+  }
+}