[MOS-855] Restore process update

Fixed issues with restoring from legacy backups
and cases when the database set fetched from backup package
is different than the system one.

[MOS-853] Purge multimedia database when initializing indexer

When startup indexer for FileIndexer starts, it checks for
lock file. If it's not present, it starts the indexing.

Due to changes in DB initialization we have to purge the
DB before starting the init scan because of potential
restore content

[MOS-856] Another approach to MTP path in DeviceInfo

This time it's device-agnostic from purefs paths

[MOS-855] Fix restore from legacy backup

Added checking if requested to restore backup
from pre-UDM version and setting db versions
to zero in such case, as version info file
(called backup.json in legacy backups) doesn't
contain info about versions.

[MOS-856] Update DeviceInfo documentation

Updated docs for DeviceInfo endpoint

[MOS-856] Add MTP path to DeviceInfo endpoint

Added MTP path for products to enable MC to use it instead
of hardcoded paths

[MOS-852] Fix autolock not working in UDM version

Fix of the issue that in some cases phone
wouldn't lock automatically after given
timeout. This is not a proper fix,
rather a workaround, the whole autolock
mechanism should get refactored to
support testing via harness.

[MOS-851] Remove factory reset screen from backup and restore

Fix of the issue that factory reset screen
informing user of need to manually turn
on the phone to continue the process
was appearing also when restarting to
backup or restore.

[MOS-000] Fixed tests for update

Fixed tests for performing update, now it does not require
developer endpoint

[MOS-000] Bump binaries and add Bell target

Change binary assets versions for both
products, fixed missing dependencies
in Bell's CMake, added 'Bell' target
that automatically builds the
image.

[MOS-807] Removed read code

Removed dead code
Fixed Harmony relaxation app assets path

[MOS-807] Fix MTP root path

Fixed MTP root paths for both Harmony and
Pure due to the MTP implementation
not supporting hierarchical directories.

[MOS-000] Update binary versions

Bumped up versions of binaries

[MOS-807] Update scripts

Added minor tweaks and fixed bugs.

[MOS-000] Fix for test_updater

Fixed outdated method in harness

[MOS-807] Update scripts

Added update scripts for both variants:
UDM update and further 'normal' updates.

Minor updates to the directories layout

[MOS-807] Unpacking update package

* Added unpacking and validating of
update package
* Removed 'utils-bootconfig'
* Added 'tar' module
* Minor compilation issues fixed

[CP-1734] Create factory reset reboot UI

Create window that will be shown when the
device turns off first time after factory
reset request made from PureOS.

[CP-1421] Fix backup, restore and device info tests

Fix of the aforementioned tests after changes
implemented in PureOS.

[MOS-835] Fix version.json entry

Renamed boot to os