Fix image-builder scripts

* Fix encoding issues
* Convert all files to UTF-8
* Fix indendation and hanging whitespaces
* Add new vairable LIBVIRT_IMAGES_DIR to be able to use faster drive for KVM images
* Fix unattended template for sysrep on Windows Server 2008 R2

Change-Id: Ifb4df8c0eeddf1698a6e4c691f48e92406bac770
Merge "Fix image-builder scripts"