Query the BLE base band for idle periods and put the CPU to sleep during
this time. This allows us to reduce clock speed again and wake up in
time to quickly serve BLE interrupts.

In the future we can now even go lower than DIV4, as BLE continues to
work at least until DIV16.

clock: Raise clock speed for BLE to work while sleeping

See merge request !499

feat(ecg): Experimental streaming of ECG samples via BLE

See merge request !493

mp: Correctly mask interrupts

See merge request !498

mp: fix 32 bit overflow in systick_get_us

See merge request !497

ble: Add firmware revision to device info service

See merge request !496

Indicate on screen that a reset will happen

See merge request !495

Add a boot animation to show off CTX

See merge request !494

When ctx is currently running in the dispatcher task to perform some
drawing calculations, the code here in the pmic task might preempt it.
This can lead to odd glitches and probably in the worst case a crash.
Because we know that no other code will continue running after we've hit
the shutdown codepath, we can just force-reinitialize ctx here.

Print "Reset!" to the screen before resetting so it is obvious what is
about to happen.  Currently, the screen brightness just suddenly jumps
up and card10 becomes unresponsive until the bootloader shows up.

feat(ble): Add a queue for indications and notifications

See merge request !491

Closes #237

See merge request !490

Closes #238

See merge request !489

This makes it possible to reliably stream data (like ECG samples) to another device

Closes #237

Fixes #238

hack(ci): Disable cert check for now

See merge request !492

Looks like the docker image is too old for the new LE certs

fix(sleep): Keep HIRC turned on when switching back to HIRC96

Closes #236

See merge request !488

fix(mp): Enable gatt client functionality again

See merge request !487

Update CHANGELOG

See merge request !485