(REPLATS-238) Updates for container removal of ssl.sh / cert handling

[x] https://github.com/puppetlabs/pe-puppet-server-extensions/pull/1295 should be merged prior to this
Remove CERTNAME, DNS_ALT_NAMES and WAITFORCERT from all PE container service definitions as they're not needed given:
- certs are preloaded
- ssl.sh has been removed from containers so they can't directly generate their own
  - in k8s, an initContainer specifies these values to the pe-client-tools container
  - in the shared helper gem, the pe-puppet-server-extensions repo is explicitly specifying these values in its copy of the compose file as its the only suite testing against the CA - see https://github.com/puppetlabs/pe-puppet-server-extensions/pull/1295
- Also remove PUPPETSERVER_HOST and PUPPETSERVER_PORT from the pe-puppetdb container as those values are removed
- Update the README accordingly, noting new paths to cert files that no longer use the CERTNAME convention

puppetlabs / pupperware