Run local installation of OCaml on macOS if installed

[nathanfallet]

Is your feature request related to a problem? Please describe.
When the app is running on a mac where OCaml is installed, the installed version of OCaml can be used instead of the javascript environment.

Describe the solution you'd like
When the console starts loading, check if OCaml is installed on the system, and if so, open a toplevel from it.

Additional context
Can use Process class on macOS: https://www.hackingwithswift.com/example-code/system/how-to-run-an-external-program-using-process
Check if ocaml is installed:

if which ocaml >/dev/null; then 
  echo "ocaml installed"
else
  echo "ocaml not installed"
fi

[nathanfallet]

What left:

• Use readabilityHandler (see https://stackoverflow.com/a/38088651/8261566)
• Check for local installation (just check if ocaml executable file exists)
• Fix comment removal (currently not optimized at all)
• Sync in and out in the console (not all inputs and then all outputs)