An extension point on the frontend for Catalog Customization

[deshmukhmayur]

Provide a clear and concise description of the feature request

The upstream backstage allows granular customization options for the Default Catalog Index, such as Custom Filters, Custom Columns, Actions, etc. Including props for Initially Selected Filter, Kind, and table options.

There should be some way to customize the catalog with similar options in Janus.

Backstage Catalog Customization: https://backstage.io/docs/features/software-catalog/catalog-customization/

Describe the problem that this feature resolves

Since the catalog index plugin is mounted as default, there's no way to customize the catalog index to add a custom filter to filter the entities by a custom property, or to add an additional column to the Catalog Table.

Acceptance Criteria

A way to customize the catalog index plugin (frontend) using the an extension point.