feat: add nested option support

[Litarnus]

Adds support for nested options through the OptionsResolver. It supports specifying defaults using nested array syntax, for example

$resolver->setDefaults([
    'foo' => [
        'bar' => 'baz',
        'test' => [
            'example' => '1234'
        ],
    ],
]);

Specifying the defaults will also register them as a schema, meaning that setting values that don't have defaults are rejected and log messages are emitted that they have been rejected.

To specify allowed values/types or normalizers, it's possible to use . (dots) as separators, for example:

$resolver->setAllowedTypes('foo.test.example', 'string');

$resolver->setAllowedValues('foo.bar', ['baz']);

When setting an invalid value, it will either use the defaults if no other value exists or will fall back to the existing value