operator: Add support for memberlist bind network configuration

[periklis]

What this PR does / why we need it:
This PR adds support to configure the memberlist bind_addr field using the pod network IP range instead of the default private network range used (See ). In managed Kubernetes/OpenShift cluster environments as well as in special on-prem setup the private IP range might not be available for using them. With this change set the LokiStack administrator can choose as a bind address the current pod network IP assigned by the cluster's pod network.

apiVersion: loki.grafana.com/v1
kind: LokiStack
metadata:
  name: lokistack-dev
  namespace: openshift-logging
spec:
  size: 1x.small
  hashRing:
    type: memberlist
    memberlist:
      instanceAddrType: podIP
  storage:
    schemas:
    - version: v12
      effectiveDate: 2022-06-01
    secret:
      name: test
      type: s3
  storageClassName: gp2-csi
  tenants:
    mode: openshift-logging

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• CHANGELOG.md updated
• Changes that require user attention or interaction to upgrade are documented in docs/sources/upgrading/_index.md

[Red-GV]

lgtm

[periklis]

Self-review

[xperimental]

I think I tried all the permutations of specifying options now... just a small improvement to the validation I came across and then we're good 🙂