unified list command for all scripts

e.g. ./build boot roms list
./update blobs inject listboards
./build boot list
./build clean list

also this is now possible:
./build list
or maybe
./update list
^ would list directories in resources/scripts/build
and resources/scripts/update respectively

this script is added:
resources/scripts/build/command/options

call it like so, e.g.
./build command options resources/coreboot

this script is now used, for list functions in
other scripts.

Signed-off-by: Leah Rowe <leah@libreboot.org>

resources/scripts/update/blobs/inject

@@ -44,7 +44,8 @@ main()
 	sname="${0}"
 
 	[ $# -lt 1 ] && err "No options specified."
-	[ "${1}" = "listboards" ] && listboards && exit 0
+	[ "${1}" = "listboards" ] && \
+		./build command options resources/coreboot && exit 0
 
 	archive="${1}"
 
@@ -345,16 +346,6 @@ modify_gbe()
 	rm -f "${_gbe_tmp}"
 }
 
-listboards()
-{
-	for boarddir in "${cbcfgsdir}"/*; do
-		[ -d "${boarddir}" ] || continue
-		board="${boarddir##${cbcfgsdir}/}"
-		board="${board%/}"
-		printf "%s\n" "${board##*/}"
-	done
-}
-
 usage()
 {
 	cat <<- EOF