file scheme missing in URLs when fetching local files

[antoniogarrote]

When we are parsing local files, we are storing the URL without the file scheme.
This is making my REPL fail when trying to build java.net.URI objects.

I have tracked the error to the fetchFile https://github.com/mulesoft-labs/amf/blob/master/amf-jvm/src/main/scala/amf/remote/JvmPlatform.scala#L40 function in the platform implementation for the JVM and JS/server.

We are building the Content object only with the path there.