Add link in summary to processinglog for reduced data

[phirstgemini]

1. Web endpoint to display processing log data
2. Link to it in summary page

[phirstgemini]

Added extra stuff in processinglog to be able to associate logs with reduced files. It's slightly non-trivial as there may not be a processing log, and there could be multiple processing logs if the processing was run multiple times.

Will need to select the most recent not failed one that captured files that includes that filename in it output_files and is for the same processing_tag.

Should be some example GHOST data after the weekend with the new values.

Likely need to add indexes on some of the processinglog columns - output_files, processing_tag at least.