Consider making METAREFRESH_IGNORE_TAGS an empty list by default

[Gallaecio]

As a way to allow users to fix #1422, #3768 introduced the METAREFRESH_IGNORE_TAGS setting.

To keep backward compatibility, the setting was introduced with ['script', 'noscript'] as default value. However, to reproduce the behavior of web browsers, it seems the right value would be [].

Should we switch the default value of the METAREFRESH_IGNORE_TAGS setting to [], even though the change breaks backward compatibility?