licensing: more cleanups and convertion to chromite libs
licensing: more cleanups and convertion to chromite libs

- moved main code to main() function
- board is now passed down to objects since it's not a global anymore.
- fixed all instances of pylint W0621
- killed all uses of subprocess, switched to RunCommand
- squelshed most of the useless spam from equery unpack
- refactored ReadUnknownEncodedFile
- all opens are now inside with open as foo

BUG=chromium:197970 chromium:271812

TEST=ran the script compared output vs prior output.

Change-Id: I6a86956ba333e2e606452f1493353d75491594b9
Reviewed-on: https://chromium-review.googlesource.com/167922
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Queue: Marc MERLIN <7073d0fab1ea36cd0c0f1f603a2a5e44b931b31c@chromium.org>
Tested-by: Marc MERLIN <7073d0fab1ea36cd0c0f1f603a2a5e44b931b31c@chromium.org>

chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite