Make metadata directory name match report filename

Description

Each PDF report has an associated metadata directory containing details of the calibration, including the information needed to reproduce it. But we noticed that the name of the report and the name of the metadata directory are in different formats, with slightly different timestamps.

This takes the report name and reuses it for the metadata directory.

FXE_DET_LPD1M-1_correct_003338_r120_230512_152319.pdf
FXE_DET_LPD1M-1_correct_003338_r120_230512_152319/

I've also tightened the requirements for passing in --report-to a bit, to simplify the code; if passed, it's simply treated as a path to a file, not special casing names of existing directories or folder-less file names. The .pdf extension is still added if not given, though.

Closes #76.

How Has This Been Tested?

TBD

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected) - more restrictive --report-to

Checklist:

• My code follows the code style of this project.

Reviewers

@schmidtp @ahmedk