* Change var to const for js constants being injected into the page from the server
* Allows the before_play_start event to determine if the lti content item picker should be displayed
* Move picker display function into a common controller
* Add an api method that’ll validate and sign a content item selection lti request
* injects LTI_MESSAGE_TYPE and LTI_KEY js constants into the picker page template
* LTILaunch gains a method to load the lti config that is associated with a lti key
* Updated a few strings that specifically mention canvas
* Moves all classes, tests, migrations, and configs from fuel/app/modules/lti into fuel/app
* overhaul lti test provider to simplify
* simplify lti launch picker code when sending content selection messages to lti/assignment
* fixed issue with starting plays with referrer urls longer than 255 characters fixes ucfopen#1418
* updates oauth validation in fuel by ensuring the request uri is not masked by FuelPHP
* Overhaul lit test provider a bit - mostly to simplify and use lessons
* fix code sniff errors
* add deps to docker image
* attempt to fix yarn cache issue
* Changes docker build process to ensure the built image has admin:make_paths_writable run to avoid having to run it every startup