RNH sleep state

[ThirteenFish]

The RNH should have a low power/sleep state. This should not on by default and should only be able to turn on when the following conditions are met:

• Shorepower (BQ24725 ACOK) is disconnected.
• All ports are off.
• A Rocketnet Command Interpreter command has been issued that indicates that it is safe to go to sleep.

When in sleep mode the RNH has

• Turned off the Ethernet switch (KSZ8999)
• Entered the ARM low power state.

While in this state it cannot respond over ethernet.

The only way to revive the RNH from its sleep state is to re-attach shorepower.

[kwilsonpdx]

Sequence note: Turn off all peripherals, then sleep. Other procedural checks need review.