tidy up and simplify new CDP registry entries; add explicit Subject.doAs when VOSpaceAuthorizer calls CredClient

moved tests from internaql code; made CertificateDAO configurable via constructor args; fixed CredClient to put daysValid as param

moved ost of the internal code to cadcCDP-Server and re-org packages; made CredClient able to perform both CDP and get-proxy-cert actions

changed code so the certificate chain is only appended to signed cert in the delegate method and never when caller invokes other public methods manually