Improve ARAX's ranking algorithm

[chunyuma]

This is a super issue for "Better Ranking". I split it into the following few sub-tasks:

• [ ] Adjust weights in the ranker. See the sub-task in #2300.
• [ ] Add a function in ranker to give higher weight based on the number of edges. See the sub-task in https://github.com/RTXteam/RTX/issues/2301.
• [ ] Gather examples and write a few test cases for evaluation. See the sub-task in https://github.com/RTXteam/RTX/issues/2302.
• [ ] Final evaluation after deployment.