Switch to using port 5000 for dev server

Have new OAuth client that doesn't need root nor /etc/hosts hack

Change-Id: I726e6d745a578b534f227dd949d9bc24ae8d3942
Serve and consume JSON output data with proper content-type

Change-Id: Ic61def45aeb6eb57c114ec2344927d0e3c8b52d4