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/typings/cancan.d.ts

@@ -0,0 +1,35 @@
+declare module "cancan" {
+  namespace CanCan {
+    interface Option {
+      instanceOf?: ((instance: any, model: any) => boolean) | undefined;
+      createError?: (() => any) | undefined;
+    }
+  }
+
+  class CanCan {
+    constructor(options?: CanCan.Option);
+
+    allow<T>(
+      model: any,
+      actions: string | ReadonlyArray<string>,
+      targets: T | ReadonlyArray<T> | string | ReadonlyArray<string>,
+      condition?:
+        | object
+        | ((performer: any, target: any, options?: any) => boolean)
+    ): void;
+
+    can(performer: any, action: string, target: any, options?: any): boolean;
+
+    cannot(performer: any, action: string, target: any, options?: any): boolean;
+
+    authorize(performer: any, action: string, target: any, options?: any): void;
+
+    abilities: {
+      model: any;
+      action: string;
+      target: any;
+    }[];
+  }
+
+  export = CanCan;
+}