Adding CSA14 GTs and enabling pre-mixing in autoCond.py

Updates autoCond.py by adding the GTs for the pessimistic scenario (aka 50 ns) in CSA14, 
- POSTLS170_V6 GT
-- updated AlCa conditions for the 50 ns CSA14 scenario
-- technical fixes (a.k.a. migrations of the accounts in prod)
-- enabling Ecal full readout for pre-mixing
-- adding SiStrip offsets for APV cycle phase producers.
- POSTLS170_V7 GT
-- enabling Ecal full readout for pre-mixing
-- adding SiStrip offsets for APV cycle phase producers.