rm unneeded formatting variables

Supp_zOR_vax.py
- remove variables unneeded for plotting
benchmark factors vs. zOR and benchmark

Supp_bench_benchmarkfactors.py
- benchmark index vs. each of the benchmark factors (raw
data)
- all appear to be well-correlated
- correlation coefficients need to be masked for nan

Supp_zOR_benchmarkfactors.py
- retro zOR vs. each of the benchmark factors (raw data)
- all appear to be well-correlated
- corr coef need to be masked for nan

functions.py
- benchmark index factor import (benchmark_factors_import
function)