(GH-209) Refactor the session state to be a class and pass that instead of global modules

[glennsarti]

Fixes #209

The Puppet Editor Services - The PuppetHelper, queues and providers. have organically grown and are now a gnarled mess. Time to pay down some of the tech debt.

Refactor the from message-handler up in the stack.

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• [x] Create session_state style class and attach it to the message_handler

• [x] Move sessions specific stuff into session_state

• [x] Refactor for new DocumentStore

  • [x] Create a duck-type module for the new class
  • [x] Make tests and rubocop pass
  • [x] Finish refactoring EVERYTHING and get rid of the ducktype module

• [x] Refactor the PuppetHelper into the session_state where applicable

  • [x] move loaders and xxxx_loaded? methods to session_state
  • [x] Get rid of connection_id module variable
  • [x] Get rid of cache module variable
  • [x] ducktype?

• [x] Refactor object_cache

  • [x] This is done as part of the PuppetHelper refactor

• [x] Refactor queues from modules to class

  • [x] Single Instance queue
  • [x] Validation
  • [x] Sidecar
  • [x] Migrate single instance tests from validation/sidecar to single_instance_queue

• [x] decouple object hierarchy in client_state Ideally we shouldn't need known object hierachies and should uses events/delegates e.g. don't do @connection_id = message_handler.protocol.connection.id

At this point the refactor is done but nothing has been improved

• [x] What improvements to make?
  • [x] Make the documents a 1st class object, not a hash. Means we can cache AST and token lexing. Later PRs will add the caching etc. This PR only makes it possible to add those features.
• [x] ~Add End-to-End integration test (like the debug server) to smoke test the entire system.~ Seperate PR