provide HA for pushing metrics data by prometheus in member cluster

[willzgli]

What would you like to be added:

1. set the remotewrite address as a domain name "storage.monitor.tke.com" in member cluster's prometheus configuration
2. add ingress rule on global cluster for forwarding metrics data to infuxdb from member clusters
3. set the A record of "storage.monitor.tke.com" as the vip in prometheus deployment

Why is this needed:

using master[0]'s ip as the influxdb address exists a signle point of failure.