Vulkan ICD update

[Roderick Colenbrander]

Hi all,

Last year I shared my wine-vulkan icd work
(https://github.com/roderickc/wine-vulkan). Since then I made many
changes and the code is in a much better shape now.

I would like to ask people interested in Vulkan to try it out and
report issues (on github). I just want to make sure the core Vulkan
code is working properly now before I start submitting patches to Wine
in the future.

In particular I would like to know the stability of the nasty 32-bit
struct conversion code (enabled on 64-bit as well for testing). If it
works correctly I can finally rebase these nasty changes across the
other commits, which is something I would like to do only once.

Other improvements like support for child window rendering and more
extensions are in the pipeline.

Changes:
- Rebased on Wine 3.0
- Perform win32 <-> host struct conversion when needed.
- Improved driver model, where WSI ('WGL') now lives in the graphics driver.
- Improved X11 integration including client window rendering.
- Support for major games including Doom 4, Wolfenstein II and Talos Principle.
- Many other bug fixes.

Thanks,
Roderick