Is it possible to change the template_directory?

You can filter template_directory_uri:

<?php
add_filter( 'template_directory_uri', function( $template_dir_uri ){
    return str_replace( 'http://example.com', 'https://cdn.example.com', $template_dir_uri );
});

This will change URIs so they point at a CDN subdomain served via HTTPS.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)