Ansible for AWS runners

[chantra]

This stack does quite a few things:

• allow setting runners with ansible on AWS
• use kvm when pssible (bare-metal) and also allow setting multiple runners per repo
• add architecture in the runner label see kernel-patches/vmtest#162 for context.
• add support to run runners using a GH app instead of a GH user, this helps runners not being impacted/impact rate limiting
• add a runner prefix