Optional seed in MillipedeWilks traysegment

[mlincett]

The current MillipedeWilks reco traysegment takes an optional seed:

skymap_scanner/skymap_scanner/recos/millipede_wilks.py

Lines 257 to 260 in c0d20ef

	if seed is not None:
	logger.debug('Updating StepXYZ')
	self.UpdateStepXYZ(coars_steps, seed.dir, 150*I3Units.m)
	self.UpdateStepXYZ(finer_steps, seed.dir, 3*I3Units.m)

Currently, that argument is hardcoded to:

skymap_scanner/skymap_scanner/client/reco_icetray.py

Line 158 in c0d20ef

seed=pframe[f"{cfg.OUTPUT_PARTICLE_NAME}"],

It seems to me that we can get rid of the additional argument, and just default to updating the steps according to cfg.OUTPUT_PARTICLE_NAME (?)

@tianluyuan I am taking care of this as part of #244 since I have to modify the traysegment arguments nevertheless. Let me know if you have comments.

I see this is a bit more tricky than I thought, because the "steps" live at the segment instance scope, while the frame is accessible only when the segment is run. Probably the most idiomatic way of doing this would be to store the steps inside the frame? This goes a bit beyond the scope of #244 and is rather connected to #230