Add group aliases and configurable content ordering to entity page

Add two new configuration features for entity page groups:

- Group alias IDs: groups can declare aliases so that content targeting
  an aliased group ID is included in the aliasing group
- Configurable content ordering: a new contentOrder option (alpha/natural)
  controls how content items within each group are sorted, with support
  for both a page-level default and per-group overrides. The new default
  is alpha (alphabetical by title).

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/app/app-config.yaml

@@ -48,6 +48,8 @@ app:
     - page:catalog/entity:
         config:
           showNavItemIcons: true
+          # default content order for all groups, can be 'alpha' or 'natural'
+          # contentOrder: alpha
           groups:
             # placing a tab at the beginning
             - overview:
@@ -58,6 +60,9 @@ app:
             - documentation:
                 title: Docs
                 icon: docs
+                # example aliasing a group
+                # aliases:
+                #   - docs
             - deployment:
                 title: Deployments
             # example adding a new group