refactor code that replaces api-docs path in swagger-ui

[pjfanning]

Newer "org.webjars" % "swagger-ui" jars put the petstore url in a swagger-initializer.js so current code does not replace the path when these newer jars are used

[pjfanning]

@gerbrand would you be interested in looking at this?

[pjfanning]

I've removed the use of webjars from https://github.com/pjfanning/swagger-akka-http-sample and use a simpler solution that redirects to the Petstore swagger ui but gets it to load the sample's swagger.json. I am considering archiving this project and stopping further support.