Backport sprint Izmir to `maintained` branches

Created by: fdobrovolny

The following PRs were merged:

PR	maintained/v5.x	maintained/v5.0.x
#499 Ca rotation	❌ (#460)	❌
#502 Updates doc: default cilium version	🌴 Jena (Breaks cilium tests conformance)	❌
#501 Bumps cilium to v1.14.0 and cilium-cli to 0.15.0	🌴 Jena (Breaks cilium tests conformance)	❌
#498 Fix/fullclean namespace	❌	❌
#494 Fix delete_cluster.sh and others to handle per cluster ns on os #492 (closed)	❌	❌
#445 Option to deploy harbor	🌱	❌
#493 Ensure kubeconfig for cluster namespaces	❌	❌
#491 Fix cacert templating	❌ (#460)	❌
#431 Make cilium the default CNI.	❌	❌
#475 Add script that updates cluster files from R4 to R5	❌	❌
#489 Pass conformance tests with cilium	🌱	🌱
#481 Separate k8s clusters by namespace #228 (closed)	❌	❌
#460 Custom CA	❌	❌
#486 Ignores .envrc	❌	❌
#477 Add migration steps for existing k8s clusters to adopt #432	🌱	❌
#487 Fix yamllint warnings	❌	❌
#485 Update github actions	❌	❌

We should decide what should be backported if anything.