Added Initial skeleton for ebay data crawling - > Strategy Used - Ebay Sitemaps from Robots.txt

Entry Point -
Main
   MarketPlace Factory - Give me the That I need to crawl - will give the target
         Strategy Factory -  Give the way how we are going to crawl our above target
             Now we reached to our strategy that is ebay robotstxt strategy

Currently we are only supportingmarketplace ebay and strategy robotstxt

Packages-
common - common classes used by all marketplaces
ebay-
  robotstxt
  uisearch
  api

util - utility classes used throughout the code.

Basic Flow -
ebay sitemap url will give the list of some .xml.gz file url -
So target is to get those .gz, extract them and get the main listings xml file. This work is done by our UrlRetriever component
Now the DataExtractor component will hit those listings urls and extract the actual data from html.