Packer bootstrap tweaks

Much speed by using our Geo mirror + maximum freshness by not hard coding the bootstrap version anymore + extreme future-proofness by creating the temporary server with Ubuntu 22.04. ️

roles/install_arch/tasks/main.yml

@@ -42,9 +42,14 @@
 - name: touch LOCK file on mountpoint
   file: path=/mnt/LOCK state=touch owner=root group=root mode=0644
 
+- name: fetch latest bootstrap version
+  set_fact:
+    bootstrap_version: "{{ lookup('url', 'https://geo.mirror.pkgbuild.com/iso/latest/arch/version') }}"
+  when: bootstrap_version == 'latest'
+
 - name: download bootstrap image
   get_url:
-    url: https://mirrors.kernel.org/archlinux/iso/{{ bootstrap_version }}/archlinux-bootstrap-{{ bootstrap_version }}-x86_64.tar.gz
+    url: https://geo.mirror.pkgbuild.com/iso/{{ bootstrap_version }}/archlinux-bootstrap-{{ bootstrap_version }}-x86_64.tar.gz
     dest: /tmp/
 
 - name: extract boostrap image  # noqa 208