Remove the scriptz submodule and hard-commit the files.

The submodule is a leftover from when this project was intended to work
as a series of microservices. It was meant to provide common
functionality to the builds for every microservice. That's no longer the
case, and the submodule is a pain-point both in on-boarding new
developers and running the Docker build.

script/include/global_header.inc.sh

@@ -0,0 +1,12 @@
+# global_header.inc: Any basic things that should be executed at the
+#                    beginning of any and every script
+
+# If any command fails, immediately exit the script
+set -e
+
+# Ensure the working directory is the app root directory
+cd "$(dirname "${0}")/.."
+
+# Source all function definition files
+
+source ./script/include/helper_functions.inc.sh