astakos: Move ExceptionHandler in views.util
It is view-specific and did not deserve a separate file.
astakos: move get_menu service under astakos im services
get_menu is used only by astakos cloudbar:it should not be under astakos api services
astakos: unified settings handling
Import astakos settings module instead of importing specific settings
astakos: remove unused imports
astakos: reorganize views