Migrate functional-red-black-tree to Js-sdsl OrderedMap

[ZLY201]

Hey! I'm the developer of Js-sdsl. Official website: https://js-sdsl.github.io/

Now, we published the version 4.1.4.

I see you are using functional-red-black-tree.

In benchmark, we have confirmed that Js-sdsl is several times faster than functional-red-black-tree.

We would like to invite you to migrate red-black tree related functions to Js-sdsl v4.1.4 and I am willing to submit a pull request for this change.

Looking forward to your reply! :D