[Bug 45616] New: winecfg: allow setting windows version via CLI

https://bugs.winehq.org/show_bug.cgi?id=45616

Bug ID: 45616
           Summary: winecfg: allow setting windows version via CLI
           Product: Wine
           Version: 3.13
          Hardware: x86
               URL: https://github.com/Winetricks/winetricks/blob/master/s
                    rc/winetricks#L2355
                OS: Linux
            Status: NEW
          Keywords: download, integration, source
          Severity: enhancement
          Priority: P2
         Component: programs
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: Gentoo

This has been a FIXME in winetricks for years. While reviewing stuff recently,
I ran across it and looked into it. I wasn't able to find a (closed) bug for
it, and I think it's worth opening one now.

Currently, winetricks has to replicate all the logic needed to set a particular
Windows version (i.e., major/minor version, service pack version, etc.). This
can also include if it's a server version of windows or not, etc. When Wine
changes a SP version, winetricks has to catch up later, and it can lead to
subtle bugs (e.g., https://github.com/Winetricks/winetricks/issues/970)

It would greatly simplify things if instead, winecfg (or some other program,
but winecfg seems most appropriate) could change windows versions via a CLI
argument. E.g.,
$ wine winecfg winver=winxp

would set winxp mode, and act appropriately for win32/win64.

This should return an error if someone tries to set an invalid version, e.g.,
$ wine winecfg winver=doesnotexist

or
$ WINEARCH=win64 wine winecfg winver=win98