Add basic Python Click skeleton.

This commit adds a basic Python Click skeleton.

scripts/bosun.py

+import click
+
+
+@click.group()
+def cli():
+    """Bosun is a GitLab bolt-on for Liberty-style project management."""
+
+
+@cli.group()
+def greet():
+    pass
+
+
+@greet.command(name="world")
+def world_greet():
+    """Shows 'Hellow world!' message."""
+    print("Hellow world!")