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/presenters/group.ts

@@ -0,0 +1,12 @@
+import { Group } from "@server/models";
+
+// @ts-expect-error ts-migrate(2749) FIXME: 'Group' refers to a value, but is being used as a ... Remove this comment to see the full error message
+export default function present(group: Group) {
+  return {
+    id: group.id,
+    name: group.name,
+    memberCount: group.groupMemberships.length,
+    createdAt: group.createdAt,
+    updatedAt: group.updatedAt,
+  };
+}