Add static method to delete databases

With v0.2 we will have this api as an options for specifying a VFS:

```js
import { IdbFs } from "@electric-sql/pglite";
const pg = new PGlite({
fs: new IdbFs("my-database")
})
```

We should add a `delete` static method to the VFS interface that deletes the database from the underlying storage:

```js
import { IdbFs } from "@electric-sql/pglite";

IdbFs.delete('my-database')
```