[cli] added distributed launcher command (#791)

* [CLI] add CLI launcher

* Revert "[CLI] add CLI launcher"

This reverts commit df7e6506d4.

* [CLI]add cli launcher feature

* remove testing message used during developing

* refactor the module structure.

colossalai/cli/cli.py

@@ -0,0 +1,54 @@
+import click
+from colossalai.cli.launcher.run import main as col_launch
+
+class Arguments():
+    def __init__(self, dict):
+        for k, v in dict.items():
+            self.__dict__[k] = v
+
+@click.group()
+def cli():
+    pass
+
+@click.command()
+@click.option("--hostfile", 
+                type=str,
+                default="")
+@click.option("--include",
+              type=str,
+              default="")
+@click.option("--exclude",
+                type=str,
+                default="")
+@click.option("--num_nodes",
+                type=int,
+                default=-1)
+@click.option("--num_gpus",
+                type=int,
+                default=-1)
+@click.option("--master_port",
+                type=int,
+                default=29500)
+@click.option("--master_addr",
+                type=str,
+                default="127.0.0.1")
+@click.option("--launcher",
+                type=str,
+                default="torch")
+@click.option("--launcher_args",
+                type=str,
+                default="")
+@click.argument("user_script",
+                type=str)
+@click.argument('user_args', nargs=-1)
+def launch(hostfile, num_nodes, num_gpus, include, exclude, master_addr, master_port, 
+           launcher, launcher_args, user_script, user_args):
+    args_dict = locals()
+    args = Arguments(args_dict)
+    args.user_args = list(args.user_args)
+    col_launch(args)
+
+cli.add_command(launch)
+
+if __name__ == '__main__':
+    cli()