Update to CMSSW_9_4_11, deep tagger changes

• update to CMSSW_9_4_11
• get DeepAK8 from official CMSSW version instead of private implementation
  • had to define some "normalized" discriminators manually for mass decorrelated tagger
• add DeepDoubleB discriminators
• add BasicJetRemover to remove low-pt useless AK8 jets as the very first step, since discriminators are now added in updateJetCollection()

Using updateJetCollection() to add btag discriminators at the same time as updating JECs produces an error message, but it seems to be spurious. As long as the correct output collection is selected, all the JEC factors, JER factors, etc. come out identically.

The official DeepAK8 is slightly faster than before, but DeepDoubleB takes about twice as long as DeepAk8, so the overall event rate drops slightly (9.71 ev/s to 8.25 ev/s).