Show number of rows processed on Validation Results page

[Stephen-Gates]

Provide confidence that the whole file was processed especially when you use the "Validate Again" button and the CSV behind the URL may have changed in size.

Important to know if processing completed or a large file size resulted in only part of the file being processed. Especially given the warning on the /About page

[quadrophobiac]

this is a small fix that is currently stalled due to below. progress so far at https://github.com/theodi/csvlint/compare/show-number-of-rows-processed

• resolve CSVlint .env to run locally without problems noted in File uploads hang on dev instance of CSVlint #281
• decide on utilising csvlint gem method line_limit_reached as a way of testing this addition
  with planned testing additions of
• write tests for stress test fixtures (multiples of 1000 rows and 1MB and 10MB file size)