Single Must Use Plugins Directory for local development

Yes, you can set the WPMU_PLUGIN_DIR constant in the config file of each of the sites (and WPMU_PLUGIN_URL for the url).

By default it is defined as:

WP_CONTENT_DIR . '/mu-plugins'

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