compat: deno install `file:` protocol

[lukeed]

Version: Deno 2.1.6

When running deno install in an existing node project (using its package.json file), it should be able to install/link local files and directories as dependencies.

see https://docs.npmjs.com/cli/v11/commands/npm-install#install-links

{
  "dependencies": {
    "foobar": "file:./foobar"
  }
}