Feature/vcluster

[mysiki]

Add support of VCluster (https://www.vcluster.com/) (resolve my issue : #415)

VCluster (VC) work on top of physical cluster with workload sync between virtual cluster and physical cluster. During the sync, VC rename the pod to avoid naming collision. VC only sync the pod, not the other stuff like RS, Deployment, ... The sync is done on the physical namespace where vcluster is present.

Summarize design :

Physical cluster Namespace	Physical cluster pod name	Virtual cluster Namespace	Virtual cluster pod name
vcluster-foo	myappfront-1234-x-myappns-x-vclusterfooname	myappns	myappfront-1234
vcluster-foo	myappback-123-x-myappns-x-vclusterfooname	myappns	myappback-123
vcluster-foo	otherapp-1234-x-otherappns-x-vclusterfooname	otherappns	otherapp-1234
vcluster-foo	otherapp-4567-x-otherappns-x-vclusterfooname	otherappns	otherapp-4567
vcluster-foo	otherappwithreallylongnammmmme-1234567891234567891234-x-othera-f5fef5e6fe	otherappns	otherappwithreallylongnammmmme-1234567891234567891234

The renaming is done following algo present in added function get_vcluster_pod_real_name.

To reduce pod number and cluster load, usually metrics are read read from physical cluster (avoid to have all exporter pod inside VC).

Because of VC only sync pod, KRR need to run connected to the VC (to detect DP, STS,..). But the pod name and pod namespace in prometheus are the one present in physical cluster.

This PR add 2 new arguments that are mandatory to calculate the pod name and pod namespace for prom query and function to use it.
I also add debug logger on prom query (can be remove if you think is useless :) )

Readme is update

Test done with success on my VC (with VC args) and without (like before this change).

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