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/groupMembership.ts

@@ -0,0 +1,19 @@
+import { GroupUser } from "@server/models";
+import { presentUser } from ".";
+
+type GroupMembership = {
+  id: string;
+  userId: string;
+  groupId: string;
+};
+
+// @ts-expect-error ts-migrate(2749) FIXME: 'GroupUser' refers to a value, but is being used a... Remove this comment to see the full error message
+export default (membership: GroupUser): GroupMembership => {
+  return {
+    id: `${membership.userId}-${membership.groupId}`,
+    userId: membership.userId,
+    groupId: membership.groupId,
+    // @ts-expect-error ts-migrate(2322) FIXME: Type '{ id: string; userId: any; groupId: any; use... Remove this comment to see the full error message
+    user: presentUser(membership.user),
+  };
+};