labtunnel: added labtunnel installer, command, and readme

BUG=None
TEST=Installer script, all options, tunnel operations tested for
successful connections.

Change-Id: Ib50a2698cb964e8c83433a2e17f3f1d9b496eac7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/3508556
Reviewed-by: danny chan <dchan@chromium.org>
Reviewed-by: Vinayak Suley <vsuley@chromium.org>
Tested-by: Jared Bennett <jaredbennett@google.com>
Reviewed-by: Shijin Abraham <shijinabraham@google.com>
Reviewed-by: Katherine Threlkeld <kathrelkeld@chromium.org>
Commit-Queue: Jared Bennett <jaredbennett@google.com>
6 files changed