3rd reland "Add luci-go tool to be fetched via CIPD"

This is a reland of 3bcc71d83f6d9af93a7408fbea34f6d5f0185c03

Now code search should be fine.

Original change's description:
> Add luci-go tool to be fetched via CIPD
> Do not remove the adhoc mechanism on GCS that predates CIPD yet, as the recipes
> need to be updated.
> Change analyze to not ignore changes to isolate.
> R=tandrii@chromium.org
> Bug: 851596
> Change-Id: Ic068db83dea4c3a0f17b55181de523b16c9838a5
> Reviewed-on: https://chromium-review.googlesource.com/1097623
> Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
> Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#569688}

Bug: 851596
Change-Id: Icd227efde182ff844e93dbb692124c1297ab0d7c
Reviewed-on: https://chromium-review.googlesource.com/1135791
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Marc-Antoine Ruel <maruel@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#574787}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8181595470db26090b29814229390edfb5727dca
3 files changed
tree: 8c677d3a20e8f353386eac8a22b47d31dd5cb322
  1. .gitignore
  3. README.md
  4. linux64/
  5. mac64/
  6. win64/


Contains executable built out of https://chromium.googlesource.com/infra/luci/luci-go/+/master/client/cmd Mapped through CIPD.