[Webservice] Move list of three gain/run detectors into webservice config yaml

Description

This MR is addressing this issue https://git.xfel.eu/calibration/pycalibration/-/issues/96 for avoiding adding the parts of new detector names everytime in the webservice code and avoid regular MRs like this one: !954 (merged)

How Has This Been Tested?

Tested on xcaltst@max-exfl-cal002

Relevant Documents (optional)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist:

Reviewers

@schmidtp @kluyvert