feat(apis_entities): replace apis_entities merge route

The `get_merge_view_url` is being replaced by a generic
`get_select_merge_or_enrich_url`. It does basically the same, but lives
in the `generic` app.

apis_core/apis_entities/templates/apis_entities/partials/entity_actions_nav.html

@@ -15,7 +15,7 @@
               <span class="material-symbols-outlined material-symbols-align">content_copy</span> Duplicate
             </a>
             <a class="object-merge dropdown-item"
-               href="{{ object.get_merge_view_url }}">
+               href="{{ object.get_select_merge_or_enrich_url }}">
               <span class="material-symbols-outlined material-symbols-align">cell_merge</span> Merge
             </a>
           {% endif %}