arch: arm: SecureFault Handling for Cortex-M33

This commit contributes the implementation of the SecureFault
handling for ARMv8-M-based Cortex-M33. The implementation is
compiled conditionally with compile-time directive
CONFIG_ARM_SECURE_FIRMWARE, which is to signify the intention to
build a Secure image on ARMv8-M with Security Extensions.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>