[Timepix] Store labels assigned to pixels

Description

The Timepix centroiding notebook groups pixels together to centroids. So far only the resulting centroids were saved and the information which original pixels were assigned to which centroid was lost. This MR also records the labels assigned to each pixel.

How Has This Been Tested?

run = 307  # required
in_folder = '/gpfs/exfel/exp/SQS/202430/p900421/raw'  # required

Types of changes

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

Checklist:

• My code follows the code style of this project.

Reviewers

@ahmedk @bjoerns