Refactor filter logic
Refactor filter logic

The filter list now supports boolean logic:
- For now, three filters (NamespaceFilter, NewPageFilter, ExistingPageFilter) will always be applied using AND, while the remaining filters will be applied using OR.
- In the future, we can also support arbritrary combinations by using a new input syntax.

ds

danmichaelo/UKBot,danmichaelo/UKBot,danmichaelo/UKBot