suggestion: reboot with rescript core?

[JUSTIVE]

Seems that the Rescript team is going to remove Belt from the Rescript compiler and language(see), I suggest moving forward to rescript-core bindings, which is the new standard library in Rescript ecosystem.

I guess some of the bindings and APIs currently we've got won't match to rescript core's, but it's a matter of time the belt is going to be removed from the rescript, we have to move ASAP.

And, I think it will bring good momentum to reboot this library.