[EGD-6355] Adjust MuditaOS to be used with Secure Boot

The start address of the OS image adjusted to comply with HAB
Secure Boot. Proper SNVS initialization performed at system startup.
SNVS drivers updated to most recent version. Image signing can be
performed as a part of build process. See doc/secure_boot.md for
more info.

[EGD-5661] Add power management for filesystem

Add peripheral control (USDHC and PLL2 clocks)
for file system support.
This will save energy and extend battery life.

[EGD-6110] Cyclic db write

WAL option used, checkpoint set to 1

[EGD-5632] Remove "systemStarted" from "DeveloperMode" EndPoint

Remove `systemStarted` field as it's no longer used.

[EGD-6545] Enable magnetometer LPDCM mode

To be able to reduce the power usage of the phone, magnetometer
has been switched into interrupt driven LPDCM mode. Added some
fixups maintaining current behavior on startup and disabling
the tethering mode

[EGD-6344] Fix SystemView compilation

Add necessary FreeRTOS configurations to run SystemView

[EGD-6499] Fix audio initialization

Now the peripherals and the audio clocks will be turned on
only when the user is using the audio, which will save energy.

[EGD-6597] Add PM control for all disc in DM

This patch add API for send power control message
for all disc registered in the disc manager. It is needed
for power management for suspend resume all discs.

Signed-off-by: Lucjan Bryndza <lucjan.bryndza@mudita.com>

[EGD-6506] Turn on function keys backlight during call

Backlight of function keys are on when call is active.
When call ends, previous backlight mode is restored.

[EGD-6452] Sound selection GUI

Sound selection GUI used to change ringtone, message sound and
notification sound in settings.

[EGD-6563] Don't allow to edit exponent output in calculator

Clear the calculator input field before typing if it contains exponent
output from previous calculations.

[EGD-6301] Add Connecting to the network in intervals

It implements mode Offline Messages only - connecting to
the GSM network in defined by user intervals and rejecting
incomig calls during connected phase. It also implements
handling of connetion interval setiing and small fix in modes
popup.

[EGD-5773] Device becomes not responsive when opening settings

Use asynchronous communication with service cellular
to obtain own number.

[EGD-6590] Add /mfgconf mount to iosyscalls lib

Add translation of the /mfgconf mount point in the libiosyscall
library when redirection is disabled.

[EGD-6426] Fix sim card not being detected

Adds selected sim read from settings.

[EGD-6118] BT low power initial implementation

The `Pure`'s power consumption was measured in three variants:
 * BT off
 * BT on (master)
 * BT on (EGD-6118)

Measurement results (respectively):
* idle [mA]:
 ** 78-81
 ** 83-85
 ** 78-81

* BT headphones connected [mA]
 ** -
 ** 85-87
 ** 82-85

* music play [mA] (may be not precise)
 ** 90-100
 ** 98-105
 ** 101-115

[EGD-6527] Internationalization API unification

Single api to rule i18n
all calls to localistaion in cpp files unified
cut off ass many dependencies in i18n header as possible

[EGD-6485] Remove Cellular message types from global

Domain-specific message types should not pollute global space.

[EGD-3649] Fix paths in UT

Reorganization of assets left path in UT outdated.

[EGD-6313] Fix Display backlight settings are not presistent

Add global scope to settings db function calls