Seed for random in SETools [BUG]

[aguinot]

In SETools there is the possibility to select randomly a subpart of a catalogue randomly. When this is done, the random generator is not seeded so we cannot reproduce the results.
This could have an impact on the PSF model (hopefully a small one). If the same exposure is processed twice, and we split the catalogue to have a training and validation set, there will not be the same for both processing. This results in two different PSF model for the same exposure.

A seed should be added in the config file or/and a way to generate a seed based on the exposure name to avoid this behavior.