Make it simpler to customize favicon

[eauchat]

Thanks for the great theme.
Trying to customize the favicon I saw that it seem to be defined with:

 <link rel="icon" type="image/png" href="{{ url('theme://images/favicon.png') }}">

in the base template.
This makes it not trivial to customize the favicon. Practically the site admin needs to customize the theme, using inheritance.

Are you interested in adapting the code to make it simpler for site admins to use their own favicon. If yes, I can write a PR for it.

[IHash223]

This would be helpful