ios: rss request - implement add feed POST request
ios: feed vc - implement add new feed feature
ios: rss request - implement delete feed request
ios: feed vc - implement delete feed handler
ios: core data - update news item model

+ user feed id
+ news id
ios: core data - fetch all feeds fix duplicates
ios: NSUserdefaults - implement login logic
ios: NSUserdefautls - add reset keys method
ios: register vc - implement register process
ios: login vc - remove scaffold implementation
ios: implement refresh news/feeds