new intent service/pipeline api

[JarbasAl]

moves the backwards_compat decorator from ovos-workshop to also be used here

companion to OpenVoiceOS/ovos-core#349 + OpenVoiceOS/ovos-plugin-manager#177

TODO - document new bus events properly from pipeline plugins

# NOTE: these receive skill_id/name separately, not as part of munged names
  self.bus.on('intent.service:detach_intent', self.handle_detach_intent)
  self.bus.on('intent.service:detach_entity', self.handle_detach_entity)
  self.bus.on('intent.service:detach_skill', self.handle_detach_skill)
  self.bus.on('intent.service.register_intent', self.handle_register_intent)
  self.bus.on('intent.service.register_keyword_intent', self.handle_register_keyword_intent)
  self.bus.on('intent.service.register_regex_intent', self.handle_register_regex_intent)
  self.bus.on('intent.service:register_keyword', self.handle_register_keyword)
  self.bus.on('intent.service:register_entity', self.handle_register_entity)
  self.bus.on('intent.service:register_regex_entity', self.handle_register_regex_entity)
  self.bus.on('intent.service:train', self.handle_train)

compatibility with the previous api provided via @backwards_compat decorator

  # backwards compat handlers with adapt/padatious namespace
# NOTE: these receive munged intents, skill_id/name need to be extracted from name
  self.bus.on('padatious:register_intent', self.handle_register_intent)
  self.bus.on('padatious:register_entity', self.handle_register_entity)
  self.bus.on('register_vocab', self._handle_adapt_vocab)
  self.bus.on('register_intent', self.handle_register_keyword_intent)
  self.bus.on('detach_intent', self.handle_detach_intent)
  self.bus.on('detach_skill', self.handle_detach_skill)
  self.bus.on('mycroft.skills.initialized', self.handle_train)