New Feature: Outbound random selection for urlTest based on best latency.

[ashly-right]

This feature provides a simple load balancer with a random/least-latency strategy. This update should be completely backward compatible.

An attribute named "randomize" was added to the urlTest outbound. the default value is false.

Functionality:
When randomize is set to true, the application makes a list of the best latency each time and selects one of them randomly for each new connection.

[ashly-right]

@nekohasekai Dear
Could you please review this request whenever you can? Thank you very much.

[ashly-right]

@CodingMoeButa Thank you very much for your comment and test. You are right, there is a slight problem with the startup regarding the first testing

Pure randomization is a good solution for crawler purposes when you have tested the proxies before. But we need a solution for testing and randomization for an anti-censorship app. because we need to establish a reliable connection within all possible proxies.

I can implement a separate random outbound as well. but the question is whether the repository owner wants these features or not. I couldn't find a contribution rule. I hope one of the repo admins helps me.

[scplay]

Hope new feature like load balancer in clash, poll and hash map