* [xmsh] add support for xmsh library
- xmsh is a mesh document format. xmsh library is the reference
implementation for the format.
* [xmsh] removed extraneous file command
* [xmsh] update version to v0.2.3
* [xmsh] upgrade to version v0.3.1
* [xmsh] update to version v0.4
* + fix python executable packaging
* [vcpkg_find_acquire_program] Fix PYTHON3 on non-Windows