Add --skip-ro-app option (#396)

Add --skip-ro-app option (#396)

The "--ni-regen-all-app" option performs AOTC again for all installed apps.
If the "--ni-regen-all-app" option is performed after FOTA (OTN),
an error may occur or unnecessary AOTC may be performed by running AOTC for an app installed in the RO area.

To avoid this situation, the "--skip-ro-app" option is added.
If this option is set, native image regenration for apps installed in the RO area is skipped.

Note! this option works with "--ni-regen-all-app" option only.