Remove the declaration of the graphite::server class; the resource declarations of the subclasses apply what we need.
Explictly require the OS and Pip package install classes before we try to manage or template any files, since they're only in after the OS and Pip packages put them there.
Don't apply the repo class, since it doesn't have any resources; I'm keeping it there in case some part of the installation later on needs OS package repos configured.