GDPR-Compliance & local file cache

[Webklex]

Hi, Thanks for creating this project :)

I've noticed that there are two remote scripts called, if a graph gets rendered. This is somewhat problematic regarding GDPR-Compliance.
In order to fix this I've created a local cache, which downloads the file in order to serve them locally.

I've added this method to Render::class:

public static function cache($filepath, $source): void {
    if (File::exists($filepath) === false) {
        if (File::exists(dirname($filepath)) === false) {
            File::makeDirectory(dirname($filepath), 677, true);
        }
        File::put($filepath, file_get_contents($source));
    }
}

.. and adjusted Render::html a bit, to use the cache instead:

$jqueryPath = public_path("js/jquery-3.4.1.slim.min.js");
$assetPath = public_path("js/mermaid@{$version}/dist/mermaid.js");
        
self::cache($jqueryPath, "https://code.jquery.com/jquery-3.4.1.slim.min.js");
self::cache($assetPath, "https://unpkg.com/mermaid@{$version}/dist/mermaid.js");

$html = [
    '   <script src="' . asset("js/jquery-3.4.1.slim.min.js") . '"></script>',
    '   <script src="' . asset("js/mermaid@{$version}/dist/mermaid.js") . '"></script>',
    ...
];

Kind regards & happy coding,