Add FlowCollector config that controls how slices are globally managed:

• Enable flag
• per-tenant collection mode: AlwaysCollect or AllowList
• admin allow-list: list/regex of namespaces not concerned by per-tenant config, and still managed directly from the cluster-scope config

A warning must be displayed if per-tenant is enabled and loki is enabled but not in LokiStack mode (because data is not isolated between tenants in that case)

Example of configuration:

  processor:
    slicesConfig:
      enable: false
      collectionMode: AllowList
      namespacesAllowList:
      - /openshift-.*|netobserv.*/ 

When slicesConfig is globally disabled, everything should work as usual. Creating FlowCollectorSlices have no effect.

When enabled + AlwaysCollect, the FlowCollectorSlices are only used to allow configuring subnets. namespacesAllowList is ignored.

When enabled + AllowList, in addition to the above, the FlowCollectorSlices are also used to collect flows on the namespace where it is installed (with overrideable flow sampling); ie namespaces where no FlowCollectorSlices exist, and not in the centralized "namespacesAllowList", will not have any flow

Precision: a flow is collected if either its source namespace or its destination namespace is allowed.