feat(epicardium): Add v1.17 splash

See merge request !463

Make sleep work again when BLE is disabled

Closes #231

See merge request !466

In commit 4944aa48 ("fix(ble): Update to changes from new SDK")
a call to `BbDrvDisable()` was added to `sleep_deepsleep()`.  This
function must, however, only be called when BLE was previously
initialized, otherwise a wakeup from deepsleep will not be possible (if
it ever reaches it?).

Fix this by reworking the BLE enabled check to also be usable here, to
only call `BbDrvDisable()` when BLE is active.

Fixes: 4944aa48 ("fix(ble): Update to changes from new SDK")
Fixes: #231

Add config option to disable low battery check

Closes #227

See merge request !464

We have encountered a device where the connection from the PMIC's ADMUX
pin to the MCUs ADC is severed and thus the low battery check would
trigger immediately.

For making such devices still usable, add a config option to disable the
low battery check entirely.

Fixes: #227

See merge request !460

With sphinx 3 a ton of warnings about unresolvable xrefs are generated.
Add a workaround to silence them.

Ref: https://github.com/sphinx-doc/sphinx/issues/8945

Don't lint vendored sources...

Update vendored hawkmoth sources to commit upstream
69cde0b2c5315e46bf431a4c7c8b92cf47a544a6.

Use a newer container with Sphinx 3 installed.

fix(sdk): Prevent endless loop on I2C error

Closes #226

See merge request !465

The read operation needs to wait until the stop bit it sends on error is
handled. Otherwise a following write operation will loop.

Closes #226

Ubuntu only ships clang 10 so python3-clang 11 is not working.  Fix it
to the older version.

BLE: Re-use open connection in pycardium

See merge request !461

feat(ble): Don't send DM and ATT events until disc/cfg complete

See merge request !459

feat(ble): Delay epic con open ind until epicardium is done

See merge request !458

BLE: Use synchronous BLE events and ATTC write queue

See merge request !455

Our interrupts are already scheduled via `mp_schedule()`. By switching
to the synchronous interface we avoid yet another `mp_schedule()` call
in the bluetooth module. This also allows the bluetooth module to not
have to use its internal ring buffer.

PNG support

See merge request !457

BLE fixes

See merge request !454

This fixes a potential system panic if there is already an interrupt pending

fix(display): Do not free user memory in blit

See merge request !453

change(mp): Plug in MP v1.14

See merge request !452