strengthen the fixed IP for stateful application

[weizhoublue]

What would you like to be added?

the fixed mode could be two types:

(1) normal: it behaves in the way what is doing currently

(2) reserved: it could support the scaling up and down. The IP could be reserved after the stateful application scale down. When the application is deleted , all IP address will be released.
the stateful application requiring this capability could add a designated annotation