[lubynets]

1. Currently the KF mother objects are created for all decays with 3-prong topology: $\rm{pK}\pi$, $\pi\rm{K}\pi$ and $\pi\rm{KK}$. This PR proposes conditional creation of them, only if particular decay is requested via configurables.
2. Fixed logic of invariant mass constraint application: it makes sense only when a single mother particle species is requested. This PR introduces a check for it.
3. Provided a guard against KF reconstruction of charm nuclei, since it is not implemented (yet).
4. Minor fixes: move hardcoded KF reconstruction mode to configurables, add consts, etc.

[github-actions]

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