InternalParseBeforeLinks clean-up for easier transition

- Renamed ContentProcessor to InTextAnnotationParser
- Moved InternalParseBeforeLinks to SMW\MediaWiki\Hooks ns
- Changed RedirectPropertyAnnotator signature to inject a Title instead
- Added SMW\MediaWiki\MagicWordFinder to isolate MW dependency
- Simplified related tests

Relates to #295, bug 62856