Add flag to control source of HostCfg

Default: stboot loads HostCfg from /etc/host_configuration.json at the initramfs (same as security configuration)

Add flags --host-config and --host-config-name --host-config=initramfs (default) load from initramfs with default path --host-config=efivar load from efivarfs with default variable name --host-config=legacy load from partition with label "STBOOT" with default path

--host-config-name=<_filepath or variable name_>

Examples: no flag provided: Load from /etc/host_configuration.json at the initramfs --host-config=initramfs --host-config-name=custom/path/cfg.json : Load from initramfs but override default path --host-config=efivar Load from efivars using a default ID/var name --host-config=efivar --host-config-name=STYADDA-d736a263-c838-4702-9df4-50134ad8a636 : Load from efivars but using custim efivar ID and name