tailwind: Allow configuring custom tailwind server build (#11921)

This adds the ability to configure the `tailwindcss-language-server`
integration to use a custom build of the server.

Example configuration in Zed `settings.json`:

```json
{
  "lsp": {
    "tailwindcss-language-server": {
      "binary": {
        "arguments": [
          "/Users/username/tailwindcss-intellisense/packages/tailwindcss-language-server/bin/tailwindcss-language-server",
          "--stdio"
        ]
      }
    }
  }
}
```

This will cause Zed to use its own Node version and run it with the
given arguments.

**Note**: you need to provide `--stdio` as the second argument!

It's also possible to use a custom Node binary:

```json
{
  "lsp": {
    "tailwindcss-language-server": {
      "binary": {
        "path": "/Users/username/bin/my-node",
        "arguments": [
          "/Users/username/tailwindcss-intellisense/packages/tailwindcss-language-server/bin/tailwindcss-language-server",
          "--stdio"
        ]
      }
    }
  }
}
```

This is *super handy* when debugging the language server.

Release Notes:

- Added ability to configure own build of `tailwindcss-language-server`
in Zed settings. Example:
`{"lsp":{"tailwindcss-language-server":{"binary":{"arguments":["/absolute/path/to/tailwindcss-language-server/bin/tailwindcss-language-server",
"--stdio" ]}}}}`