Introduce dist-git init command

Create new command sub-group dist-git for dist-git
related functionality and introduce the init command
that initialises a dist-git repository config with jobs
for release automation.

See packit dist-git init --help

Fixes packit/packit-service#2301

packit/cli/dist_git.py

@@ -0,0 +1,16 @@
+# Copyright Contributors to the Packit project.
+# SPDX-License-Identifier: MIT
+
+"""The 'dist-git' subcommand for Packit"""
+
+import click
+
+from packit.cli.dist_git_init import init
+
+
+@click.group("dist-git")
+def dist_git():
+    """Subcommand to collect dist-git related functionality"""
+
+
+dist_git.add_command(init)