add manage command and shell welcome message

archivebox/cli/archivebox_manage.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+
+__package__ = 'archivebox.cli'
+__command__ = 'archivebox manage'
+__description__ = 'Run an ArchiveBox Django management command'
+
+import sys
+
+from ..legacy.config import OUTPUT_DIR, setup_django, check_data_folder
+
+
+def main(args=None):
+    check_data_folder()
+
+    setup_django(OUTPUT_DIR)
+    from django.core.management import execute_from_command_line
+
+    args = sys.argv if args is None else ['archivebox', *args]
+
+    args[0] = f'{sys.argv[0]} manage'
+
+    if args[1:] == []:
+        args.append('help')
+    
+    execute_from_command_line(args)
+
+
+if __name__ == '__main__':
+    main()