New MC 2021 restripping production

MC production of D^{0}\rightarrow K^0_S \pi^+ \pi^- \pi^0 decays with 2021 restripping:

• 2017 (Stripping29r2p2);
• 2018 (Strippin34r0p2).

Includes only doubly tagged B \to D^{\ast-} \mu^\pm X decays from the Bhadron stream.