Add Dst->D0(->KsPipPim)Pip NoBias Line

The MR adds a "No bias" line for the Dst-tagged D0->KsPipPim line.

It avoids any selection on the Pi pair coming directly from the D0, in order to avoid any bias on the secondaries fraction. Tighter selections are applied on the Ks, the same that are applied at HLT1 level by TwoKs line. An filter on HLT1 lines is applied. Accepted lines are TrackMVA, TwoTrackKs and TwoKs.

Its main purpose it's to be used as a control channel for the D0->KsKs. It can be very interesting also for other charm analyses, as it provides a sample of D0->KsPiPi without any bias on the Pi pair system coming from the D0.

Impact of the new line has been measured on real HLT1-filtered data (run 289924).

Rate (NoBias line) = x1.9 rate(DstpToD0Pip_D0ToKsPimPip_LL_LowBias) ~ 3.5 kHz (from data estimates). BW(kshh module w/ NoBias) = x1.84 BW(kshh).

bw:

• + 21 MB/s added to charm kshh module (from MC)

An additional rate/bw reduction can be applied, if necessary (Dm < 155 MeV or a prescale). However, if this configuration is affordable it could be interesting for several charm measurements.

This MR is also used to test all the Charm open MRs:

!3300 !3462 !3388 !3445 !3362 !3237 !3286 !3458

FYI @gtuci @gpunzi @tpajero @fbetti