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

server/.jestconfig.json

@@ -5,9 +5,13 @@
     "<rootDir>/server",
     "<rootDir>/shared"
   ],
+  "moduleNameMapper": {
+    "^@server/(.*)$": "<rootDir>/server/$1",
+    "^@shared/(.*)$": "<rootDir>/shared/$1"
+  },
   "setupFiles": [
     "<rootDir>/__mocks__/console.js",
-    "./server/test/setup.js"
+    "./server/test/setup.ts"
   ],
   "testEnvironment": "node"
 }