Synch up to the mcu-tools/mcuboot rev 4030aac5

Synch up to the https://github.com/mcu-tools/mcuboot/commit/4030aac5944e5105f45bfcb02b7e0065810a8aeb



- Switched zephyr port from using FLASH_AREA_ macros to FIXED_PARTITION_ macros
- Made flash_map_backend.h compatible with a C++ compiler
- Enabled watchdog feed by default
-  Allowed to get the flash write alignment basing on the zephyr,flash DT chosen node property

Merged using GH web gui.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>