Add helper script to build/run the site locally

While developing pages it's quite useful to be able to run and browse
the website locally; Add a trivial helper script to setup a docker
container to do just that.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

run-hugo.sh

+#!/bin/sh
+
+# Run hugo in server mode and let it bind on all interface in the container
+# such that docker can forward it properly.
+
+# Website will be available at  http://localhost:1313/ while this is running
+REPO=$(dirname $(realpath $0))
+
+docker run \
+  -p 1313:1313/tcp \
+  -u $(id -u) \
+  -v ${REPO}:/src \
+  klakegg/hugo \
+  server