Support to start a cluster in a single node

[openinx]

Now we cann't start a zookeeper cluster in a single node, because current config design can not specific different port for different process with the same job name.

we need to change the host part from:

hosts:
  - 127.0.0.1

to

hosts:
  127.0.0.1/port=9001/id=1:  # host.1
    config:
      zoo.cfg:
        - clientPort=2181
        - server.1=zoo1:2188:3188
  127.0.0.1/port=9001/id=2:  # host.2
    config:
      zoo.cfg:
        - clientPort=2281
        - server.2=zoo1:2288:3288
  127.0.0.1/port=9001/id=3:  # host.3
    config:
      zoo.cfg:
        - clientPort=2381
        - server.3=zoo1:2388:3288

BTW, the base_port part can be removed now.