Use RatingSystem control in RatingFilter

[WithoutPants]

Uses the RatingSystem component in RatingFilter. Makes it easier to filter by rating and fixes issue where ratings with decimal points could not be filtered.

Defaults to 5 stars for single value modifiers and 1 and 5 stars for range modifiers - this is 2 and 10 in decimal rating system. It's not perfect, but provides an initial value at least.

[skier233]

Tested and looks good to me

[WithoutPants]

Also added tweak to styling for decimal rating on the performer page to address the issue that @JanJastrow reported.