Create tracking functions for explorer/catalog index features

[mrtopsyt]

Create tracking functions for the following events on the tracker, relating to index features on explorers and catalogs. Provide the following dimensions and the event_count metric:

• entity_selected
  • entity_name
• entity_table_paginated
  • entity_name
  • pagination_direction
• entity_table_sorted
  • entity_name
  • column_name
  • sort_direction
• file_downloaded
  • entity_name
  • related_entity_id
  • related_entity_name
• filter_selected
  • filter_name
  • filter_value