removed sub module stuff

cookiecutter.json

 {
     "repo_name": "repo_name",
-    "project_name": "project_name",
     "author_name": "Manu Musterperson",
-    "first_subpkg": "sub_package"
+    "module_name": "module_name",
 }
\ No newline at end of file

hooks/pre_gen_project.py

+import re
+import sys
+
+
+MODULE_REGEX = r"^[_a-zA-Z][_a-zA-Z0-9]+$"
+
+module_name = "{{ cookiecutter.module_name}}"
+
+if not re.match(MODULE_REGEX, module_name):
+    print(
+        "ERROR: The project slug (%s) is not a valid Python module name. "
+        "Please do not use a - and use _ instead" % module_name
+    )
+    # Exit to cancel project
+    sys.exit(1)