Add manylinux_2_28-aarch64 image and fix qemu path in 2_34 variant

Add a new manylinux_2_28-aarch64 cross-compilation image targeting
AlmaLinux 8 (glibc 2.28) for building portable Python wheels for
aarch64 from x86_64 hosts. Based on the manylinux_2_34-aarch64
variant with adjusted glibc (2.28) and kernel headers (4.18).

Also fix CMAKE_CROSSCOMPILING_EMULATOR in the 2_34 Toolchain.cmake
to use /usr/bin/qemu-aarch64-static (matching what the Dockerfile
actually installs).

manylinux_2_28-aarch64/xc_script/install_deps.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+
+# AUTHOR: odidev
+# DATE: 2021-07-20
+# DESCRIPTION: This file will be invoked by cibuildwheel when before all is set.
+#              It will install the package in manylinux container and copy back
+#              the installed files on host machine will will be coppied to
+#              toolchain
+
+install_dir='/host/tmp/install_deps'
+packages=$(echo $1 | sed 's/\(yum\s*\|install\s*\|-y\s*\)//g')
+
+# Installing the packages
+echo "Installing dependencies: $packages"
+if $1; then
+  echo "Installed successfully"
+else
+  echo "Failed"
+  exit 1
+fi
+
+# Coping the installed files
+if list=`rpm -ql $packages`; then
+
+  echo "Copying dependencies files to prepare cross toolchain-"
+
+  for file in $list; do
+    test -f $file && echo "Copy $file --> ${install_dir}${file}"
+    test -f $file && install -m 0644 -D $file "${install_dir}${file}"
+  done
+else
+  echo $list
+  echo "Dependencies not resolved"
+  exit 1
+fi
+exit 0