Add Rivage autosplitter

[VisionElf]

Adds Rivage to the LiveSplit catalogue using the stable latest-release URL for the MIT-licensed ASL script.

Features include Auto Start after the first New Game loading screen or, with Start: After Cutscene, after the second; load removal; and configurable milestone splits. The script supports the Windows Steam executable documented in the technical reference.

Validation: VisionElf confirmed that the release download works and that the script works in LiveSplit. No additional game tests were run for this catalogue contribution. This change only adds the XML entry and does not replace an existing autosplitter.

Developed by Codex under the supervision of VisionElf.

If you are adding or modifying an Auto Splitter, please fill out this checklist:

• My Auto Splitter does not contain any malicious functionality and I'm entirely responsible for any damages myself. (Any kind of abuse in an Auto Splitter will result in an immediate ban.)
• I am not replacing an existing Auto Splitter by a different author, or I have received permission from the author to replace the existing Auto Splitter.
• The Auto Splitter has an open source license that allows anyone to fork and host it.