(FACT-699) Add `rubyplatform` and `system32` facts

Adds `system32` fact on Windows to report on the *native* system32 directory across 32/64 bit versions of ruby and windows.

Adds a `rubyplatform` fact for all platforms so that manifests can create conditions based on 32 vs 64-bit ruby.
we did something like that for systemprofiler fact on osx, and think it that was considered to be a bad convention. I checked with @nfagerlund about nomenclature, he was +1 as is.