Totally untested, change request based on change made in #2581.
It might be my first PR in CircuitPython core...
Maybe this should be confirmed by @jamesbowman
Those are the two boards that seems supported:
* Metro M4 Express
* Metro nRF52840 Express
The only Metro that this PR concern:
* Metro M4 AirLift Lite
Other Metro I found and are maybe not supported:
* Metro ESP32-S2
* Metro M0 Express
* Metro M7 1011
This changes lots of files to unify `board.h` across ports. It adds
`board_deinit` when CIRCUITPY_ALARM is set. `main.c` uses it to
deinit the board before deep sleeping (even when pretending.)
Deep sleep is now a two step process for the port. First, the
port should prepare to deep sleep based on the given alarms. It
should set alarms for both deep and pretend sleep. In particular,
the pretend versions should be set immediately so that we don't
miss an alarm as we shutdown. These alarms should also wake from
`port_idle_until_interrupt` which is used when pretending to deep
sleep.
Second, when real deep sleeping, `alarm_enter_deep_sleep` is called.
The port should set any alarms it didn't during prepare based on
data it saved internally during prepare.
ESP32-S2 sleep is a bit reorganized to locate more logic with
TimeAlarm. This will help it scale to more alarm types.
Fixes#3786
