Make logger and prometheus optional in server config
Make logger and prometheus optional in server config

Signed-off-by: Josh Winters <3dd3a5216811ba233723a4612ec3a917850b715d@pivotal.io>
Co-authored-by: Mark Huang <222d07b3281cbd31b38f93d23c330586c713e995@pivotal.io>

wolfeidau/dex,coreos/dex,ericchiang/dex,coreos/dex,ericchiang/dex,coreos/dex,wolfeidau/dex,ericchiang/dex,wolfeidau/dex