Add basic image

It is similar to the cloud-image but it comes with a preconfigured arch
user (pw: arch) and lacks cloud-init.
6 jobs for basic-image in 31 minutes and 57 seconds (queued for 7 seconds)
Status Name Job ID Coverage
  Lint
passed shellcheck #14741

00:00:19

passed shfmt #14742

00:00:09

 
  Build
passed build #14743
fast-single-thread

00:23:00

 
  Test
passed test-basic-qemu #14745

00:02:46

passed test-cloudimg-qemu #14746

00:08:37

passed test-vagrant-boxes-format #14744

00:00:39