servo: create common ap-driver

Beating the login hurdle is one aspect that several
servo automations might want to share. This CL introduces
a common driver for AP console communication that houses
tools to beat the login hurdle on the AP console.
Going forward common utilities to do work on the AP console
should be housed in ap.py, and automation drivers that
interact with the AP console should inherit from or use
an instance of the ap driver.

CL also shores up the logic and increases the speed to beat
the login hurdle.

BUG=chromium:760267
TEST=manual
sudo servod -b $BOARD
dut-control login
login:no
dut-control login:yes
dut-control login
login:yes

Change-Id: I253abf30e4f0c90bc915b31b8fe57d9b3a9ed4c0
Reviewed-on: https://chromium-review.googlesource.com/870028
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Ruben Rodriguez Buchillon <coconutruben@chromium.org>
Reviewed-by: Todd Broch <tbroch@chromium.org>
5 files changed