Add duplication count in distinct query results

[grantfitzsimmons]

Is your feature request related to a problem? Please describe.

Grouped records for distinct query results - works ok but it's generally not useful for us unless we can easily see the number of records that have the duplication, and to be able to export a column of those count values in the csv export

Requirements:

• Implement grouped records feature to display distinct query results (done in Record Links and Selectability Added to Distinct Query Builder #4607)
• Allow users to easily view the number of duplicated records in the result set
• Enable users to export a column of count values for the duplicated records in the CSV export.

Requested by: Dan B at CSIRO (Slack)