Update README for hpc-factory repo

• Since we changed pipeline structure, we should update the README to reflect that.
• Pipeline/packer template for users to create their own pipeline.
• Pipeline to create a blank VM with packer template

added Sprint 25-09 label

changed title from Update README to Update README for hpc-factory repo

changed the description

assigned to @louistw

added Sprint 25-10 label and removed Sprint 25-09 label

changed the description

marked this issue as related to #235

added Sprint 25-11 label and removed Sprint 25-10 label

added Sprint 25-12 label and removed Sprint 25-11 label