restful: code refactoring

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
tags: addtion of init file in tags test suite

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>
restful: testing the tags restful api

Signed-off-by: Konstantinos Kostis <konstantinos.kostis@cern.ch>