(TK-44) Add link to webrouting docs in README
(TK-44) Add link to webrouting docs in README

Add a link to the webrouting docs in the main README file to make
it easy to find.

fpringvaldsen/trapperkeeper-webserver-jetty9,rlinehan/trapperkeeper-webserver-jetty9,rlinehan/trapperkeeper-webserver-jetty9,richardc/trapperkeeper-webserver-jetty9,camlow325/trapperkeeper-webserver-jetty9,nwolfe/trapperkeeper-webserver-jetty9,camlow325/trapperkeeper-webserver-jetty9,puppetlabs/trapperkeeper-webserver-jetty9,richardc/trapperkeeper-webserver-jetty9,nwolfe/trapperkeeper-webserver-jetty9,fpringvaldsen/trapperkeeper-webserver-jetty9,puppetlabs/trapperkeeper-webserver-jetty9