Add local environment support

[delthas]

Summary

The end-to-end scripts were designed to run in GitHub Codespaces (Docker-in-Docker).
Running them locally with rootless podman on Linux exposed several issues. This PR
fixes them so the full Zenko stack can be deployed and tested on a local machine.

DNS timeouts from podman search domains

Podman injects search dns.podman into kind node resolv.conf. CoreDNS can't resolve
this domain, adding an 8-second timeout to every DNS lookup. This killed pods that
rely on fast DNS during init (e.g. ZooKeeper exceeded its liveness probe). Fixed by
adding a config.yaml for kind with networking: { dnsSearch: [] }, which strips
all search clauses.

curl hangs to localhost

get_token() in common.sh hardcoded https://localhost. Two issues: curl resolves
localhost to ::1 (IPv6) first but kind only binds on IPv4, and the scheme was
hardcoded to https but keycloak ingress uses http when ENABLE_KEYCLOAK_HTTPS=false.
Fixed with a scheme variable and 127.0.0.1.

CoreDNS can't resolve host DNS

In podman environments, the host DNS server address differs from Docker's default
(172.17.0.1). Added HOST_DNS override support in patch-coredns.sh so it
reads the nameserver from /etc/resolv.conf when running outside Docker.

Other changes

• Auto-detect rootless podman and configure kind with a delegated systemd scope
• Override VOLUME_ROOT for local development (no /mnt in local environments)
• Remove unused local registry setup from bootstrap-kind.sh
• Allow using a local zenko-operator checkout instead of always fetching from GitHub
• Make /etc/hosts entries idempotent (check before appending)
• Add documentation for required /etc/hosts pre-setup

Issue: ZENKO-5243

[bert-e]

Hello delthas,

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[bert-e]

Waiting for approval

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