Add support for a custom list of domains

[NazarenoL]

I would like to set this to trigger notification windows when using the production/canary versions of the site I work for, as well as my custom local urls.

Ideally, I could set a list of domains ("www.site.com,test.site.local") to override the extension's detection of localhosts.

[andre-ellrich-adup]

yes, I need this as well. It would be great to have a list of regexes where the plugin would be active!