B2OC: restore previous D0 mass range, cleanup and more files in hlt2_b2oc_example.py

• modified: Hlt/Hlt2Conf/options/examples/b_to_open_charm/hlt2_b2oc_example.py: cleanup and more files
• modified: Hlt/Hlt2Conf/python/Hlt2Conf/lines/b_to_open_charm/builders/d_builder.py for the D0 mass range

requested review from @shunan

assigned to @abertoli

marked this merge request as draft

added B2OC label

these are the differences in the D builder wrt master so we are back to the previous D0 mass range

approved this merge request

marked this merge request as ready

merged

mentioned in commit dcb64a49

mentioned in merge request !2821 (merged)