Provide options to limit CI workflow when testing

**Is your feature request related to a problem? Please describe.**
While testing the CI to update the low-q2 onnx model it would be useful to be able to run only detector_benchmarks and specify a particular branch. This would avoid having to update the main branch several times and potentially break things which aren't tested (due to inexperience and bugs). Also the turn around on encountering errors could be significantly reduced.

**Describe the solution you'd like**
An alternative CI workflow which can temporarily be switched on for testing specific benchmarks which provide feedback to the epic PR.

**Describe alternatives you've considered**
This might not be a common enough occurrence to develop. In hindsight there were tests which could have been carried out to ensure everything worked before merging into detector_benchmarks master.