Enable multiple instances on same installation.
    
    This keeps the default tomcat.service unchanged (except for internals),
    and adds template for tomcat@name.service services.
    
    In the new world, if you need an instance, you'll create a directory
    /var/lib/tomcats/name, create {conf temp work webapps} in it, and then
    systemctl enable tomcat@name.service.
    
    This commit doesn't contain anything related to jsvc.