Resubmit PR# 2332: Enable colorized logging on Windows

[drdarshan]

This is resubmitting my previous PR #2332. I tried out @jackfrancis's updates and they work really well. I had to delete my fork for another reason so I needed to recreate the PR with the cumulative changes.

What this PR does / why we need it: On Windows, logging prints escape codes that do not render properly. I used a workaround suggested in https://github.com/mattn/go-colorable.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

Release note:

[jackfrancis]

lgtm

[EPinci]

Looks like not all string are colorized properly (v0.14.4).
During an upgrade, only the first three lines are colorized:

INFO[0002] validating...
INFO[0008] Name suffix: 93283987
INFO[0008] Gathering agent pool names...
?[36mINFO?[0m[0009] Master VM name: k8s-master-93283987-0, orchestrator: Kubernetes:1.9.3 (MasterVMs)
?[36mINFO?[0m[0009] Master VM name: k8s-master-93283987-1, orchestrator: Kubernetes:1.9.3 (MasterVMs)
?[36mINFO?[0m[0009] Master VM name: k8s-master-93283987-2, orchestrator: Kubernetes:1.9.3 (MasterVMs)

Thank you.

[jackfrancis]

@EPinci I see the same thing (only those first 3 INFO lines are colorized), but I don't see the symptoms below it (lines starting with ?), I just see non-colorized log output.