make status.py unit-testable and add unit-tests

Summary of changes:
  - undo one mistake from previous pullreq (setting deferred.name moved back to status.py)
  - simplify create_host by moving Host-related code to components.Host and adding unit-tests there. 
  - make initialize_services top-level method and split into smaller methods.
  - separate concern of handling obsolete services-format and do it right after parsing --> consistent data structure in remaining code
  - add unit tests for initialize_services