Remove serverproviders & rarely used deployers

Unfortunatelly seems like nobody is using deployers for deploying
their clouds and mostly people would like just to execute their code.

This is first patch that helps to us focus on work that should be done

1) Remove server provides
2) Remove engines that uses server providers

After this patch we are going to refactor Engine interface
and return DevStack Engine

Change-Id: Iaaeffc3fa06255afb45ba18d300a67c843ba57dd

tox.ini

@@ -5,6 +5,7 @@ envlist = py35,py34,py27,pep8
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
+         HOME={homedir}
          LANG=en_US.UTF-8
          LANGUAGE=en_US:en
          LC_ALL=C