[Mingw-cross-env-list] Moving package metadata from index.html to src/*.mk in progress

[Nagaev Boris]

Hi list,

I am moving package list, package websites URLs and official names
from index.html to *.mk files. Please take a look to
https://github.com/mxe/mxe/pull/1602

Why it is done: https://github.com/mxe/mxe/issues/1422

I have tested all packages with build-pkg.lua and they do not break.
https://gist.github.com/d368c53a35e376e759ca12a54088eace

The list of packages on the webpage is now built with JavaScript from
JSON file. The webpage works for me, testers are welcome!
Demo: http://redjohn.tk:2709/#packages

This change is not expected to affect any workflow except adding new
packages: in new approach, a website and an official package name (if
differs from MXE package name) are specified in mk file, not in
index.html.

If no bugs are found, I would like to merge this in few days to
prevent git conflicts with other commits.

-- 
Best regards,
Boris Nagaev