Autotest: Update site remote power to use RPM Infrastructure

Updated site_host to include RPM power on, off, and cycle commands,
that implement the client side code of interacting with the RPM
Infrastructure.

Removed all the RPM specific classes from site_remote_power.py and
replaced them with one generic class that utilizes the new methods
in site_host.

Also updated hardreset in SerialHost to utilize these new methods
that it will inherit from site_host.

BUG=chromium-os:34664
TEST=Ran power_IdleServer against a machine in the lab.

Reviewed-on: https://gerrit.chromium.org/gerrit/34001
Commit-Ready: Simran Basi <sbasi@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
(cherry picked from commit d5e5e271f6c8c54bb5242fc95c609032bccb5d95)

Conflicts:

	server/hosts/site_host.py

Change-Id: I23d17ac333f7771ca5672fb4ce5c36054d2ffbdc
Reviewed-on: https://gerrit.chromium.org/gerrit/38064
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
11 files changed