New QEE HLT2 and Sprucing lines and improvements to existing lines

FYI @wbarter @jideng @lugrazet @jiuzhao @lsestini @hyin @ldufour (I tagged only those whose lines are affected/who contributed this time. Feel free to add others)

This MR merges the qee_upgrade branch into master, and is therefore a cumulation of QEE-related changes over the past several months. It includes:

• Add sprucing lines for Z \to \mu\mu, Z \to ee and their same-sign backgrounds (!1674 (merged)),
• Add sprucing lines for Z+jet, with Z \to \mu\mu and the same-sign background (!1711 (merged)),
• Addition of HLT2 lines for measuring the tracking efficiency with Z \to \mu\mu candidates (!1791 (merged); fixes in !1841 (merged) and !1949 (merged)),
• Add 43 HLT2 and 60 sprucing lines for W/Z rare decay and diboson studies (!1824 (merged)),
• Add a Z \to \mu\mu no-muon-PID sprucing line (!1841 (merged)),
• Migrate the HLT2 single, high-pT electron (!1827 (merged)) and high-pT muon (!1832 (merged)) lines to ThOr functors,
• A recent fix to follow !1926 (merged) on this branch,
• NEW HLT2 Drell-Yan lines (!1995 (merged)).

I also removed an unused pvs argument to a function we share from DiMuonTrackEfficiency.py (cc @peilian).

TODO:

• Post summaries of rates and efficiencies to the description where possible; this will take a little time.