arch: arm: mpu: implement internal API for configuring static regions

This commit implements the common ARMv7-M and ARMv8-M internal
shim for configuring static memory regions at boot time. It also
adds LOG error messages, and ASSERTS, which fire if the static
MPU region configuration is not performed successfully.

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