util/hugo: Add framework to build www.coreboot.org/Documentation

www.coreboot.org/Documentation is now built with hugo (www.gohugo.io)
based on files in this repo's /Documentation directory.

Also clarify that new additions to Documentation are under CC-BY 4.0 terms.

Change-Id: I000e15b29a182bb88b40de3d0178bf8cc54ba8af
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: https://review.coreboot.org/19881
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>

util/hugo/Makefile

@@ -0,0 +1,13 @@
+.SILENT:
+.PHONY: error public
+
+error:
+	echo please state a valid target
+	exit 1
+
+themes/hugo-material-docs:
+	mkdir -p themes
+	git clone https://github.com/digitalcraftsman/hugo-material-docs.git themes/hugo-material-docs
+
+public: themes/hugo-material-docs
+	docker run --rm -it -v $$PWD:/src -v $$PWD/../../Documentation:/src/content -v /srv/www/vhosts/www.coreboot.org/Documentation:/src/public jguyomard/hugo-builder hugo --forceSyncStatic --cleanDestinationDir