[Webservice] Use leading zeros in usr/Reports folders

Description

Adding leading zeros for runs in the correction reports file path for usr/Reports as mentioned in this issue: https://git.xfel.eu/calibration/pycalibration/-/issues/75

How Has This Been Tested?

Relevant Documents (optional)

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• configuration (/home/xcal/.config/pycalibration/webservice)for production needs to be updated during the next deployment.

Reviewers

@schmidtp @kluyvert