Support native file names in ID template function

[kvaps]

Some distros may depend on the filenames, eg. alpine have an option to download and apply apkvol file during the boot.

Problem it that file should have the name like client.apkvol.tar.gz otherwise it will fails to boot, trying to decrypt it according to it's extension.

Currently, in this command:

pixiecore boot vmlinuz-vanilla initramfs-vanilla \
  --cmdline='ip=dhcp modules=loop,squashfs,sd-mod,usb-storage modloop={{ID "modloop-vanilla"}} apkovl={{ID "client.apkvol.tar.gz"}}'

client.apkvol.tar.gz file name will be translated to other-1, that's exactly problem.

[danderson]

+1, this is a problem I had booting illumos as well. The whole file serving logic needs to be redesigned, so it's not a quick fix :(