- Configure Jenkins: install pipeline and github plugins,
  allow anonymous read access, disable setup wizard, install packages
  required by Jenkins pipeline.
- Configure build pipeline job based on the pipeline script now
  maintained at: https://github.com/tiiuae/ghaf-jenkins-pipeline

Signed-off-by: Henri Rosten <henri.rosten@unikie.com>

Deploy caddy reverse proxy, redirecting public HTTPS requests to
jenkins service on the jenkins-controller VM. No need to open port 80
as caddy can deploy let's encrypt certificates using tls-alpn-01
(over HTTPS).

Also, adds a 'persistent' state disk on jenkins-controller VM to store
let's encrypt data for caddy.

Signed-off-by: Henri Rosten <henri.rosten@unikie.com>

Stop terraform from tracking workspace-specific persistent resources.

Signed-off-by: Henri Rosten <henri.rosten@unikie.com>