Perform token introspection on generic token introspection urls

[taylorking]

Change the oauth2 block to potentially look something like

{
  "type":"oauth2",
  "provider":"generic",
  "introspectionUrl":"http://tokens.com/debug?token="
}

[mhamann]

@taylorking which oauth2 block? In the Swagger? Assuming "yes", this will result in invalid swagger, so it needs to use some sort of x- extension format.