…stead of if/else statements in Rest.php

This will add a possibility to add new Processors to handle API requests

 - added magento annotations to new created files in module;
 - modified rest controller - removed unnecessary depenancy and methods, modified dispatch method;
 - modified \Magento\Webapi\Controller\Rest\RequestProcessorInterface interface and classes that implement it - removed "canProcess" method;
 - modified \Magento\Webapi\Controller\Rest\RequestProcessorPool - now it implements RequestProcessorInterface, removed methods "_getSortedRequestProcessors" and "getRequestProcessor",
added "process" mathods which match rest request processor and call it "process" method;
 - modified webapi_rest/di.xml

…rarily msrked tests as skipped.

… class and method in topic config when request/schema attribute is wrapper class of real topic service class

…nd RequestPoolInteface

…:getRoutePath()