Add rule loader and dependencies

Co-Authored-By: Justin Ibarra <brokensound77@users.noreply.github.com>

detection_rules/__main__.py

@@ -0,0 +1,28 @@
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. Licensed under the Elastic License;
+# you may not use this file except in compliance with the Elastic License.
+
+# coding=utf-8
+"""Shell for detection-rules."""
+import os
+
+from .main import root
+
+CURR_DIR = os.path.dirname(os.path.abspath(__file__))
+CLI_DIR = os.path.dirname(CURR_DIR)
+ROOT_DIR = os.path.dirname(CLI_DIR)
+
+BANNER = r"""
+█▀▀▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄   ▄      █▀▀▄ ▄  ▄ ▄   ▄▄▄ ▄▄▄
+█  █ █▄▄  █  █▄▄ █    █   █  █ █ █▀▄ █      █▄▄▀ █  █ █   █▄▄ █▄▄
+█▄▄▀ █▄▄  █  █▄▄ █▄▄  █  ▄█▄ █▄█ █ ▀▄█      █ ▀▄ █▄▄█ █▄▄ █▄▄ ▄▄█
+"""
+
+
+def main():
+    """CLI entry point."""
+    print(BANNER)
+    root(prog_name="detection_rules")
+
+
+main()