Align custom settings method naming and tweak some inline docs
Setup the admin settings field for the Attribute Threshold setting
Introduce Attribute Threshold

Puts a threshold in place that checks whether a product match based on
attributes should be counted as valid enough. Matches that score below the
threshold (a percentage of the highest match possible) are excluded from
the related-products query.
The admin setting was already in place.
Update to 1.1.0