Merge branch 'add-hello-world-examples' into 'master'

Add a recipe for "Hello World" examples

See merge request redox-os/cookbook!363

recipes/dev/hello-world/recipe.toml

+#TODO Not compiled or tested
+[source]
+git = "https://github.com/leachim6/hello-world"
+[build]
+template = "custom"
+script = """
+mkdir -pv "${COOKBOOK_STAGE}"/usr/share/hello-world
+cp -rv "${COOKBOOK_SOURCE}"/[#,a-z] "${COOKBOOK_STAGE}"/usr/share/hello-world
+"""