[v3] Rename track to ReScript?

[tejasbubane]

Reason is now ReScript. Although there is a split in the community with reason still existing, looks like the future will be rescript with all the community efforts.

The v3 reason track does not have any exercises as of now and I am planning to work on adding some now. Before I do that, should we rename the track to rescript?

If yes, what changes are required for such a rename? - apart from renaming the directory in /languages ofcourse.