Add decfiles for Sexaquark search with Lc2595 in final state

Add dec files for the modes

• \Xi_b(5945)^0 \rightarrow (\Xi_b^- \rightarrow (anti-\Lambda_c(2595)^- S) \pi^+
• \Xi_b(5945)^0 \rightarrow (\Xi_b^- \rightarrow (anti-\Lambda_c(2595)^- \Lambda \Lambda) \pi^+
• \Xi_b(5945)^0 \rightarrow (\Xi_b^- \rightarrow (anti-\Lambda_c(2595)^- \Xi^0 n) \pi^+

with anti-\Lambda_c(2595)^- \rightarrow (anti-\Lambda_c^- \rightarrow anti-p^- K^+ \pi^-) \pi^+ \pi^- For searches for a stable DM candidate S(uuddss) with m =1.875GeV, LambdaLambda and Xi0n are expected backgrounds with the same quark content.

Another mode is added

• \Xi_b^- \rightarrow (anti-\Lambda_c(2595)^- (\Lambda \rightarrow p \pi^-) (\Lambda \rightarrow p \pi^-)) \pi^+

The \Lambda decays are not forced in the first mode, as the \Lambda \Lambda system is treated as missing mass. If we force the Lambdas, there is no need for the Xib(5945) decay since we have access to all daughters and dont need the additional kinematic constraints.