Add neutron channel for B->JpsiK

To reconstruct neutron in LHCb, we choose a golden channel B->(Jpsi->pnbarpi)K with loose cuts. In this MR, we also require to save calo information for future study with a novel method. The bw is 11.4MB/s in HLT2 line with prescale=0.01, we could decrease to 0.001 or other suitable value to be involved in B2CC. Currently calo_digits and calo_cluster information are saved.

Update, the current BW is

8.38 MB/s, in total with Lb decay, 9.9 MB/s.

Hlt/Hlt2Conf/python/Hlt2Conf/lines/b_to_charmonia/hlt2_b2cc.py

@@ -220,8 +220,8 @@ def BuToJpsiK_NeutronPrescaled_line(name="Hlt2B2CC_BuToJpsiK_NeutronPrescaled",
         prescale=prescale,
         algs=b2cc_prefilters() + line_alg,
         persistreco=persistreco,
-        calo_digits=False,
-        calo_clusters=False, 
+        calo_digits=True,
+        calo_clusters=True, 
     )