Django Creator Part 2

[fudgeu]

Adds many of the remaining features for the creator. Additionally introduces and changes some util classes, as well as a lot of cleanup. Completes much of the remaining tasks in #20 (with some exceptions)

• Ported endpoints for AI generation and set up the generator_util.py util class. Generation config is loaded in through a .env file that has the same format as the config for Materia PHP
  • Image generation was not ported however since it wasn't a feature used in the first place
  • This PR adds the openai package to requirements.txt for this functionality
• Ported endpoints for qset history. Works as expected.
• Removed question importing
• Implemented widget instance locking through an endpoint and WidgetInstanceUtil methods.
  • Though, there is no way to invite collaborators yet, etc.
• Cleaned out some old API endpoints, util classes, and related files that are no longer used due to their DRF replacements.
• Fixed a lot of linting issues
• js_global_vars now properly supports setting None, str, bool, and numbers as global JS variables appropriately (whereas before every item was just pasted in as a JS string object).
• Converted the MsgUtil class into MsgBuilder and Msg. Msg now exists as a standalone class that can be used to pass error states internally. Msg objects have .as_json_response() and .as_drf_response() to easily convert them to formats that can be sent to the client. MsgBuilder is a factory class that helps in creating many of the common message types, such as no_login or failure.
• Created the ContextUtil class and ported all existing context creations to use it. Eases the creation of Context objects, largely by auto-filling many of the required or almost-always-required fields automatically.
• Adds a UserUtil class, largely to provide a verify_session function that acts similarly to the version present in PHP
• Patches the widget installer tool to work since it relied on some internal API calls that don't exist anymore due to DRF

Things that are not included in this branch:

• Anything regarding assets, as that is still a WIP
• Expand instance ID hash size to a more future-proof variant

[clpetersonucf]

Approved, with the provision that there are some changes to things that will still need to be adjusted or deleted in the future: some examples include changes to the JS API util that are on deprecated/NYI endpoints and the Question model.

[clpetersonucf]

Pairing the qset with widget instance data in this context slipped past me - but I think I'm generally OK with having a dedicated request for it here. Keeping these resources separated feels cleaner, even if it means an additional hit on the API. I'm open to being convinced otherwise though.

[clpetersonucf]

I think I'm OK with this method existing, but anywhere that isn't using explicit boolean values should be judiciously updated to only use boolean values. One of the hard-line goals of the django rewrite is to eliminate any future uses of nonsense like foo == "1" for boolean checks.

[clpetersonucf]

These changes may be redundant if we choose to retire the Question model, but I don't see the harm in including them preemptively.