Add build with Docker, make and submodules

Starting to pull out hacks and custom instructions into a reproducible build.

build.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+docker build -t web-gphoto2 - < Dockerfile
+docker run --rm -it \
+	-v $PWD:/src \
+	-u $(id -u):$(id -g) \
+	web-gphoto2