Adds a Dockerfile and `CreatePostgresSSL.sh` script, which makes an Alpine based Postgres server with a self signed certificate. The script will drop the generated `rootCA.crt` into the `data/transient` folder.
This can then be included in the test by setting the environment variable `ENSO_DATABASE_TEST_CA_CERT_FILE`.
Test has been updated to check the various SSL connection modes.
