chore: Move to Typescript (#2783)

This PR moves the entire project to Typescript. Due to the ~1000 ignores this will lead to a messy codebase for a while, but the churn is worth it – all of those ignore comments are places that were never type-safe previously.

closes #1282

docs/ARCHITECTURE.md

@@ -1,6 +1,6 @@
 # Architecture
 
-Outline is composed of a backend and frontend codebase in this monorepo. As both are written in Javascript, they share some code where possible. We utilize the latest ES6 language features, including `async`/`await`, and [Flow](https://flow.org/) typing. Prettier formatting and ESLint are enforced by CI.
+Outline is composed of a backend and frontend codebase in this monorepo. As both are written in TypeScript, they share some code where possible. We utilize the latest ES6 language features, including `async`/`await`, and types. Prettier formatting and ESLint are enforced by CI.
 
 ## Frontend
 
@@ -19,7 +19,7 @@ app
 ├── routes      - Route definitions, note that chunks are async loaded with suspense
 ├── scenes      - A scene represents a full-page view that contains several components
 ├── stores      - Collections of models and associated fetch logic
-├── types       - Flow types
+├── types       - TypeScript types
 └── utils       - Utility methods specific to the frontend
 ```