ci: hpc gpu integration test

[theissenhelen]

Description

This PR adds a workflow to run integration tests on a gpu on the HPC. It runs nightly at 22 pm.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Issue Number

Code Compatibility

• I have performed a self-review of my code

Code Performance and Testing

• I have added tests that prove my fix is effective or that my feature works
• I ran the complete Pytest test suite locally, and they pass
• I have tested the changes on a single GPU

Documentation

• My code follows the style guidelines of this project
• I have updated the documentation and docstrings to reflect the changes
• I have added comments to my code, particularly in hard-to-understand areas

Additional Notes

[VeraChristina]

This looks good to me, many thanks!

Just two small points raised in the comments:

• Do we want to add a check for the latest commit as in the current nightly workflow?
• Small questions about the pull_request_target set-up that I am not familiar with

[anaprietonem]

Great work Helen!