The BaseResource implementation in TypeScript had (and continues to have) a number of issues. A lot of this stems from just bad design decisions that were made before we even thought too much about typing or polymorphism, but some of it is just mistakes or poor understanding of TypeScript when I first converted it. This change does the following: 1. Switches the order of `TOptions` and `TExtraOptions`. I had followed what `Backbone.Model` did, but didn't realize that the spina `BaseModel` swaps them. This was making it so our call to `CombinedModelConstructorOptions` was creating errors. 2. Adds a base resource data interface, and extends that for subclasses that currently define the resource data structure. 3. Moved `payloadFileKeys` into the BaseResource implementation. This was currently only defined in FileAttachment, but it's used inside of BaseResource and by other (not-yet-typescriptified) subclasses. 4. Changed `validate` to take in a `Partial<TDefaults>` instead of `TDefaults`, which matches our usage of this method. 5. Added type labels for everything that's in `prototypeAttrs` as instance members too. This shuts up the type checker about these magical properties. 6. Properly passed in the attributes type for DraftReview. 7. Added some missing type labels. Changes 1 & 2 are technically breaking, but the only class that was affected was `ReviewRequest`, and it seems highly unlikely that any third-party code is using this yet, so I want to do it now. What this doesn't fix is our decision to override `fetch`, `save`, and `destroy` with incompatible signatures. I'm still puzzling over what to do there to make it so we don't get huge horrible warnings about any resource class not being compatible with `Backbone.Model`. Testing Done: Ran js-tests.