Add a filter to allow developers to block certain plugins from being loaded

[partiellkorrekt]

The filter can be used like this:

add_filter('bedrock_autoloader_load_plugins', function ($plugins) {
    return array_filter($plugins, function ($name) {
        return !str_starts_with($name, 'my-plugin-name/');
    });
});
new Autoloader();

This pull request solves https://github.com/roots/bedrock-autoloader/issues/34