Add token replacement support

Problem/Motivation

When using filters, it might be convenient to use replacement tokens in the replacement field. It would avoid using static values like current Drupal website URL (or part of it) that would prevent config to be exported and used without modifications on another site.

Proposed resolution

Handle token provided by the token module API. There could be all the site information elements (name, slogan, URL, contact e-mail, etc.).

If you feel like it would be a nice feature, please subscribe to this issue or post a message to let me evaluate the demand and the priority.