Changing the way how the bare-metal cluster works

[shawnh2]

In the current implementation, the bare-metal mode cluster runs in the foreground, so it supports:

• delete: does not support, but disrupting the foreground process will clean its metadata
• list: does not support
• get: retrieve the current cluster profile

It occurs to me that some users may wish gtctl will not perform delete while disrupting the foreground process (ref #155), so I propose a new way for bare-metal mode cluster to work. Since it no longer delete the metadata when the foreground process is shutting up, so:

• delete: will do as just No need to remove metadata when exit foreground bare-metal creation #155 points out
• list: will list all the cluster metadata in localhost
• get: will perform get operation on specific cluster