Only load widget when consent has been given #20

The Tawk.to Widget should not be loaded when the user has not given consent.

Most Cookie Consent banners provide a global javascript object that contains the consent and on what level consent has been given.

Multiple approaches are possible:

• set the javascript variable in the admin UI and check for it in the widget code
• pass the widget javascript to apply_filters so it can be wrapped in a javascript check
• let the widget template be overruled with a customised version by using locate_template

This last one would be my preferred approach

I'll try and create a Pull request anytime soon