Create a script for making binary drops of miTLS

[BarryBo]

The script should be run after a miTLS build completes, and populate a drop share with:

• .so/.dll
• public headers (mitlsffi.h, mitlspki.h, etc.)
• Windows import libs (libmitls.lib, libquiccrypto.lib)
• OCaml source produced during the build (required for debugging failwith errors that report .ml filename and line number)

Copying directly to an SMB server from inside Cygwin can be very slow (especially if the build machine and server are on different continents). So the files should be staged locally, and bulk-copied. The OCaml source could be tarred/zipped, to reduce copy latency, too.

@ad-l currently does this by hand. It needs to be automated, then, preferably, run during the Everest nightly build.

[BarryBo]

Closing... we are moving to a source drop format, and it is automated by the Everest make-source-drop script.