Merge pull request #17 from hmrc/AP-centos-build

AP added tempates for centos
added packer launcher script to make life easier
correction to launcher
fixed vmware centos template
fixes for centos vmware template
added debug mode to laucher script
changed disk type ID to 0 so file are not split into 2gb
Merge branch 'AP-centos-build' of github.com:hmrc/base-image-builder into AP-centos-build