Windows support for package management

[gridbugs]

This issue collects all the issues that need to be addressed in order to support dune package management on windows:

• Allow users to choose a C compiler toolchain on windows #11160
• Support installing the compiler to the toolchains directory on windows #11159
• Install the "flexdll" package in the toolchains directory on windows #11158
• The dev-switch target doesn't work on windows #11157

Additionally, we'll need to make some changes to the binary distribution to support windows:

• Build the dev preview for windows ocaml-dune/binary-distribution#139
• Install script for windows ocaml-dune/binary-distribution#140
• Windows version of the ocamllsp wrapper script ocaml-dune/binary-distribution#141

We'll also need to start building the ocamllsp and ocamlformat packages for windows:

• Build ocamlformat and ocamllsp packages for windows ocaml-dune/ocaml-binary-packages#18