Use different EQSANS chopper configuration depending on the experiment date

[backmari]

Description of work:

This PR prepares for the installation of two new choppers at EQSANS. The instrument previously had four single disk choppers (two of them paired as a double chopper), but will now have a total of single disk choppers paired as three double choppers. The chopper fixed settings (aperture, distance to source and starting phase), together with the recorded speed and phase during a run are used by drtsans to determine the neutron wavelength bands transmitted by the choppers.

drtsans will use the log start_time in the NeXus file to determine whether to calculate the wavelength bands using the old four chopper configuration or the new six chopper configuration.

There is a follow up story to update the configuration values after they have been determined by the IS, and to add testing with real data using the new choppers:
Story 15020: [drtsans] Update EQSANS chopper configuration values after choppers have been installed.

Check all that apply:

• updated documentation and checked that it looks correct in the pull request preview
• Source added/refactored
• Added unit tests
• Added integration tests
• Included a manual test for the reviewer
• Verified that tests requiring the /SNS and /HFIR filesystems pass without fail

References:

• Links to IBM EWM items: Story 13113: [drtsans] New class or update classEQSANSDiskChopperSet
• Links to related issues or pull requests:

⚠️ Manual test for the reviewer

Check list for the reviewer

• best software practices
  • clearly named variables (better to be verbose in variable names)
  • code comments explaining the intent of code blocks
• All the tests are passing
• The documentation is up to date and looks correct in the pull request preview
• code comments added when explaining intent

Execution of tests requiring the /SNS and /HFIR filesystems

It is strongly encouraged that the reviewer runs the following tests in their local machine
because these tests are not run by the GitLab CI. It is assumed that the reviewer has the /SNS and /HFIR filesystems
remotely mounted in their machine.

cd /path/to/my/local/drtsans/repo/
git fetch origin merge-requests/<MERGE_REQUEST_NUMBER>/head:mr<MERGE_REQUEST_NUMBER>
git switch mr<MERGE_REQUEST_NUMBER>
pixi shell  # activate the environment
pytest -m mount_eqsans ./tests/unit/ ./tests/integration/
exit  # exit the environment

In the above code snippet, substitute <MERGE_REQUEST_NUMBER> for the actual merge request number. Also substitute
<my_drtsans_dev_environment> with the name of the conda environment you use for development. It is critical that
you have installed the repo in this conda environment in editable mode with pip install -e . or conda develop .