Implement nested options support

[linear-code]

For the data collection, we want to support nested configuration options in our OptionsResolver.

For example:

new Options([
  'foo' => [
    'bar' => 10,
    'baz' => false
  ]
]);

It should be able to specify defaults, normalizers and allowed types for nested values too

[linear-code]

PHP-86

[sentry-pierre]

Confirmed by inspection: OptionsResolver only validates, normalizes, and type-checks top-level keys. Nested arrays pass through as opaque values.

The $path parameter names in setAllowedValues and setNormalizer suggest someone at least imagined this, but the plumbing stops at the first array depth. Clean, bounded scope.