'Move to new file' refactoring for JavaScript and TypeScript

Add a new refactoring that extracts a class or function to a new file next to the current one. For example, for the simple project:

`code.ts`:

```ts
export class Foo { }
export class Bar { }
```

If the user highlights`Bar`, the `extract to new file` action would result in:

`code.ts`:

```ts
export class Foo { }
```

`bar.ts`:

```ts
export class Bar { }
```