Re-work internal cache to better serve non-DataNode IPs

[adwk67]

The current implementation builds an internal cache of dataNode IP/Label. If the request is a non-dataNode IP, then these IPs "impersonate" the datanodes i.e. the datanode running on the same kubernetes node as the (calling) IP is used. This is inefficient as this resolution step requires at least one call-out to get all Pods in the current namespace. This can be improved by building a cache for all pod IPs in the namespace (with their labels) so that this call is not needed so often. This is shown below, with the top diagram to be replaced with the bottom one:

Also investigate if using https://github.com/fabric8io/kubernetes-client/blob/main/doc/CHEATSHEET.md?rgh-link-date=2024-02-20T14%3A54%3A24Z#sharedinformers will improve performance.