security/dogtag-pki: Enable ACME support and improve rc integration

Enable the ACME responder that was previously disabled in the port:

• Build with WITH_ACME and install the ACME webapp, configuration templates (database, issuer, realm, engine), the pki-acme-run script and pki-acme.jar
• Patch hardcoded Linux paths in the ACME components to their FreeBSD locations (/usr/local/share/pki, /var/db/pki)
• Link jaxb-api.jar and javax.activation-api.jar into the server common libs, required by the ACME webapp at runtime

Improve the FreeBSD rc.d integration:

• Generate java_opts and PKI_VERSION for the rc service directly from the instance's tomcat.conf instead of referencing an environment file
• Add remove_rc_service() to cleanly remove the rc script, the service configuration and the rc.conf knob when an instance is destroyed, and use it in the instance removal scriptlet

Sponsored by: Netzkommune GmbH