Use dune option ppx_runtime_libraries

[jchavarri]

There is a dune stanza ppx_runtime_libraries to include the runtime lib automatically.

Per dune docs:

(ppx_runtime_libraries (<library-names>)) is for when the library is a ppx rewriter or a [@@deriving ...] plugin and has runtime dependencies. You need to specify these runtime dependencies here

This would allow to get rid of (libraries jsoo-react.lib) (can update readme instructions as well)