mgmt: mcumgr: Add support for enabling Direct-XIP app address check

The commit adds Kconfig option:
  CONFIG_IMG_MGMT_REJECT_DIRECT_XIP_MISMATCHED_SLOT
that enables verification of base address Direct-XIP binary, upon
upload, and rejects binaries that would not be able to start from
available address.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>