Generate Dockerfiles from one source for maintainability. Closes #785.

docker/render_template

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import os, argparse, json
+
+import jinja2
+
+args_parser = argparse.ArgumentParser()
+args_parser.add_argument('template_file', help='Jinja2 template file to render.')
+args_parser.add_argument('render_vars', help='JSON-encoded data to pass to the templating engine.')
+cli_args = args_parser.parse_args()
+
+render_vars = json.loads(cli_args.render_vars)
+environment = jinja2.Environment(
+	loader=jinja2.FileSystemLoader(os.getcwd()),
+	trim_blocks=True,
+)
+print(environment.get_template(cli_args.template_file).render(render_vars))