Log request and use MDC similar to siesta servlet

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge remote-tracking branch 'origin/master' into log-requests-nexus-restlet-selvlet
Merge pull request #732 from sonatype/log-requests-nexus-restlet-selvlet

Log request and use MDC similar to siesta servlet