Rename NOTES*, README*, VERSION, HACKING, LICENSE to .md or .txt

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12109)

dev/release-aux/release-version-fn.sh

@@ -36,7 +36,7 @@
 # OpenSSL source directory as value.
 
 get_version () {
-    eval $(git cat-file blob HEAD:VERSION)
+    eval $(git cat-file blob HEAD:VERSION.dat)
     VERSION="$MAJOR.$MINOR.$PATCH"
     SERIES="$MAJOR.$MINOR"
     TYPE=$( echo "$PRE_RELEASE_TAG" \
@@ -102,7 +102,7 @@ set_version () {
             PRE_RELEASE_TAG="$PRE_LABEL$PRE_NUM"
             ;;
     esac
-    cat > "$SOURCEDIR/VERSION" <<EOF
+    cat > "$SOURCEDIR/VERSION.dat" <<EOF
 MAJOR=$MAJOR
 MINOR=$MINOR
 PATCH=$PATCH

dev/release.sh

@@ -681,7 +681,7 @@ B<release.sh> recognises both forms.
 =head1 VERSION AND STATE
 
 With OpenSSL 3.0, all the version and state information is in the file
-F<VERSION>, where the following variables are used and changed:
+F<VERSION.dat>, where the following variables are used and changed:
 
 =over 4