Harvester does not have correct parameters on paginated results

[eliotjordan]

Some GeoBlacklight instances expect harvester requests to include a format=json parameter. This is added as a default param to the first request:

https://github.com/OpenGeoMetadata/GeoCombine/blob/master/lib/geo_combine/geo_blacklight_harvester.rb#L199

However, subsequent requests are taken from the next link of the previous document and the parameter has been removed:
https://earthworks.stanford.edu/?f%5Baccess%5D%5B%5D=public&f%5Bdct_provenance_s%5D%5B%5D=MassGIS&format=json&per_page=100&q=%2A&page=1

This breaks harvesting functionality on some sites.

Ensure that this parameter is appended to all requests.