Merge #17029: gitian: Various improvements for Windows descriptor

9d1f971c75 gitian: Put things in the right place to begin with (Carl Dong)
71949a97a7 gitian: Eliminate rename dependency (Carl Dong)
999a9a5f5b gitian: Smaller diff with gitian-linux.yml (Carl Dong)
c4a3c25ba1 gitian: Fix README inclusion in archives (Carl Dong)
93cb974980 gitian: Use split-debug.sh for Win builds (Carl Dong)

Pull request description:

  It would seem that our `gitian-win.yml` has not been keeping up with `gitian-linux.yml`, this PR:

  1. Minimizes the diff size between `gitian-{win,linux}.yml`
  2. Eliminates the `rename` dependency

ACKs for top commit:
  laanwj:
    ACK 9d1f971c75

Tree-SHA512: 84ed47c685e12d0064c02811907ae3d0fd3c47db8773d497dcc38f0defbfb3040fd82899fb026cf355f229b906d05a1c8038a95642bb90d044afbc2e0b239af2

contrib/gitian-descriptors/gitian-linux.yml

@@ -181,7 +181,7 @@ script: |
     rm -rf ${DISTNAME}/lib/pkgconfig
     find ${DISTNAME}/bin -type f -executable -print0 | xargs -0 -n1 -I{} ../contrib/devtools/split-debug.sh {} {} {}.dbg
     find ${DISTNAME}/lib -type f -print0 | xargs -0 -n1 -I{} ../contrib/devtools/split-debug.sh {} {} {}.dbg
-    cp ../doc/README.md ${DISTNAME}/
+    cp ../README.md ${DISTNAME}/
     find ${DISTNAME} -not -name "*.dbg" | sort | tar --mtime="$REFERENCE_DATETIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}.tar.gz
     find ${DISTNAME} -name "*.dbg" | sort | tar --mtime="$REFERENCE_DATETIME" --no-recursion --mode='u+rw,go+r-w,a+X' --owner=0 --group=0 -c -T - | gzip -9n > ${OUTDIR}/${DISTNAME}-${i}-debug.tar.gz
     cd ../../