Rework custom validation demo to not use amf

[postatum]

It currently uses amf-client-js and not webapi-parser because the latter does not export following API:

1. amf.AMF.loadValidationProfile(profilePath, Environment) (code) to load validation profile with a custom Environment that implements ResourceLoaded (code);
2. amf.AMF.emitShapesGraph(ProfileName) code and code;
3. Raml10Parser.reportValidation(ProfileName, SyntaxName) code