Get refmt.js back

[pedrobslisboa]

Description

When I was working with this astexplorer-remft feature, I found that we could probably have it directly on reason refmt as printReasonAST (Or something like it).

BUT I realized that we don't have the refmt support anymore.
We have the refmt implementation at melange playground: https://github.com/melange-re/melange/blob/main/playground/dune
We could bring back the refmt reason support and then use it at melange playground.

Later, after bringing the refmt back, we could apply the printReasonAST and printOcamlAST. Does it make sense? (I can make this improvement if you guys want).

CC: @anmonteiro @davesnx