Add new WINE.md help file

WINE.md

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+https://www.winehq.org/ provides a way to run Windows binaries on Linux.
+
+Q: Why would a west developer need WINE considering west is portable Python code?
+A: To quickly put themselves in the shoes of Windows users and troubleshoot
+   Windows-specific issues without:
+
+- A Windows licence
+- A different computer to run it, or the inconvenience of dual-booting
+- The inconvenience of synchronizing source files across computers
+
+Warning: WINE is not 100% identical to Windows and WINE is _not_ able to replicate all
+issues happening on Windows. But enough issues can be reproduced, including Path-related
+issues.
+
+This is a quick and dirty recipe to run west tests using WINE.  This process is not
+officially supported and these instructions can "bitrot" and may have fallen apart by the
+time you read them: you have been warned. Please submit fixes or better ways if you know
+them. If humanly possible, keep this working over ssh. That is: without any GUI.
+
+Do NOT replace Windows by WINE to validate releases!
+
+WINE
+----
+
+First you need to install WINE. Try the following commands and your Linux distribution will
+likely tell you what packages are missing:
+
+```
+wine   --help
+wine64 --help
+wine32 --help
+```
+At least one of these must print WINE's help message before you proceed.
+
+Some distributions let you install both at the same time. To find which one the "wine"
+command currently points at:
+```
+wine cmd
+dir c:
+```
+If you see _both_ `Program Files` _and_ `Program Files (x86)`, then you are running 64 bits WINE.
+
+WENV
+----
+
+wenv seems to work and to simplify things greatly.
+https://wenv.readthedocs.io/en/latest/usage.html
+
+```
+pip install wenv
+export WENV_PYTHONVERSION=3.12.10 # or any other version that works
+export WENV_ARCH=win64            # Optional - wenv defaults to WINE 32 bits.
+wenv init
+# wenv help should now list "python" and "pip"
+wenv help
+# Among others, Python's interactive prompt shows whether it's 32 or 64 bits
+wenv python
+# Warning: pykwalify is being replaced by jsonschema, see #904 and west/pyproject.toml
+wenv pip -v install setuptools
+wenv pip -v install pyyaml pykwalify pytest pytest-xdist pytest-env
+```
+
+An alternative to the WENV_* environment variables is:
+```
+echo '{ "pythonversion": "3.12.10" }' > ~/.wenv.json
+# For WINE64
+echo '{ "pythonversion": "3.12.10", "arch":"win64" }' > ~/.wenv.json
+```
+
+Download MinGit-*-.zip from https://github.com/git-for-windows/git/releases/
+and install it in the wenv C: disk:
+```
+unzip -d ~/.local/share/wenv/win*/drive_c/MinGit/  MinGit-*.zip
+```
+
+Append this at the end of `west/pyproject.toml`
+
+```
+# TODO: find a way to do this in "wenv" instead
+# Useful tip: pytest --pytest-env-verbose ...
+[tool.pytest_env]
+PATH = { value = "{PATH};C:\\MinGit\\cmd", transform = true }
+```
+
+At last:
+```
+cd west
+wenv pytest -h
+wenv pytest -v -s -k round_trip -n auto
+```
+
+If unused, delete the current $WENV_ARCH + $WENV_PYTHONVERSION combination and reclaim a couple Gigabytes:
+```
+wenv help
+wenv clean
+wenv help
+```
+
+