[EGD-6067] Fix database performance issues

New filesystem works differently and some vFAT optimizations
backfired badly after switch.

- avoid unnecessary folder traversing
- eliminate some unnecessary fstats
- rework sqlite file driver
- reduce MMC startup delay
- fix errno bug in iosyscalls

[EGD-5837] Removed unused cellular pinmux definition

Currently unused.

[EGD-6100] Add BT device turn off handling

After BT device disconnects (e.g. because of shutdown) Pure is now
aware of this

[EGD-5512] Usb security refactor and devices pairing

Move all security related functionality to single security endpoint
Paired devices can be added to avoid further passcode requests

[EGD-4853] Add Wake up GSM modem on demand

System wakes up Cellular when there is a need to communicate
with the modem, e.g. to handle an outgoing call

[EGD-5967] Add blank screen when off

Present blank screen to
inform the user that phone
is off

[EGD-5660] Add PWM Cpu sentinel

Change of PWM frequency due
to main clock change in low
power operation.

[EGD-5204] Show passcode screen only when PC is connected

USBConfigured event is not fired when powerbank, charger is connected.

[EGD-5204] Show passcode screen only when PC is connected

USBConfigured event is not fired when powerbank, charger is connected.

[EGD-5204] Secure USB communication

Secure all endpoints by returning 403(Forbidden) when USB is connected.
Request screen passcode to enable secured endpoints.

[EGD-5204] Secure USB communication

Secure all endpoints by returning 403(Forbidden) when USB is connected.
Request screen passcode to enable secured endpoints.

Merge branch 'EGD-5737-merge-master-to-exp-lbr-fix'

[EGD-5565] USB: Fix stack size for littlefs

Update USB submodule

[EGD-5737] Fix compilation issues after merge

Master was using some fetures removed by new filesystem

[EGD-5737] Merge master into experimental

Synchronize with master before merging

[EGD-5503] Fix copyright

Previous commit related to the same ticket introduced invalid copyright
in some files. This commit fixes that.

[EGD-5503] Add watchdog implementation

The system watchdog monitors whether there is message traffic
on the Bus. If no message was sent for an extended period of time,
a reset will occur. It should also protect against system-wide hangs.

On Linux, watchdog is simulated by a FreeRTOS task that will call exit
on timeout.

[EGD-5810] Fix for old batteries

Temporary fix for old batteries

[EGD-3685] PR fixes

Included Alek's suggestions from PR

[EGD-3685] Added infinite repeat

Addef API for infinite vibra repeat

[EGD-3685] PR fixes

Fixes after PR suggestions