[Profile - Contributor Duplicates] Convert page to use HTMX

Revamp the merging of duplicate contributors (/contributor_duplicates/) workflow to use HTMX.

changed milestone to %Complete HTMXification

mentioned in merge request !51 (merged)

changed title from [Contributor Duplicates] Convert page to use HTMX to [Profile - Contributor Duplicates] Convert page to use HTMX

mentioned in commit bbdcb927

closed with merge request !51 (merged)