global: add runtime
runtimes: add runtime with k8s implementation
This is a first round of separating the k8s code from the rest of the code. It mostly moves things around and does some renames to better reflect the k8s/non-k8s aspects.
Bug: #359808
Depends-On: !69 (merged)
Signed-off-by: David Caro dcaro@wikimedia.org