Replace copy/watching of non-language assets with copy-webpack-plugin

src/@types/cpx.d.ts

@@ -1,43 +0,0 @@
-/*
-Copyright 2023 The Matrix.org Foundation C.I.C.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-declare module "cpx" {
-    export class Cpx {
-        public constructor(source: string, outDir: string, options?: object);
-
-        public on(eventName: "copy", fn: (event: { srcPath: string; dstPath: string }) => void): void;
-        public on(eventName: "remove", fn: (event: { path: string }) => void): void;
-        public on(eventName: "watch-ready", fn: () => void): void;
-        public on(eventName: "watch-error", fn: (error: Error) => void): void;
-
-        /**
-         * Copy all files that matches `this.source` pattern to `this.outDir`.
-         *
-         * @param {function} [cb = null] - A callback function.
-         * @returns {void}
-         */
-        public copy(cb: Function | null): void;
-
-        /**
-         * Copy all files that matches `this.source` pattern to `this.outDir`.
-         * And watch changes in `this.base`, and copy only the file every time.
-         *
-         * @returns {void}
-         * @throws {Error} This had been watching already.
-         */
-        public watch(): void;
-    }
-}

src/@types/loader-utils.d.ts

@@ -24,5 +24,3 @@ declare module "loader-utils" {
         maxLength: number,
     ): string;
 }
-
-export as namespace Cpx;