Encapsulate our test suite helper functions inside a module

Background:

Given how Ruby works, all def:s at the “lowest” level (i.e. outside any class or method) actually get added into the Object class (which all other classes inherit), so we actually add goodies like wait_until_tor_is_working to Object, so "some string".wait_until_tor_is_working is a perfectly fine way to call it in our test suite. :) I suppose the right way would be to encapsulate such functions in a module like this:

module Helpers
  def self.wait_until_tor_is_working
  [...]
  end
end

and then call them as Helpers.wait_until_tor_is_working. The same problem exists for the helper functions we define in the various step definition files (like configured_pidgin_accounts in pidgin.rb), so perhaps all helpers should also be added into the Helpers module at the top of each step definitions file (keeping them in the affected file is imho good for readability); multiple module statements for the same module name will just keep on building up the same one.

Hence, if we care about not polluting Object and risk more collisions of the kind we experienced in #8966 (closed) (see especially #8966-note_26), we should do this, or something similar (e.g. put them in a class).

Parent Task: #10237

Original created by @anonym on 9030 (Redmine)