ssh-known-hosts: Move ConfigMap to its own project

This will allow multiple projects to have a ConfigMap with the same
`ssh_known_hosts` contents without duplicating the source file in the
repository.

jenkins/kustomization.yaml

@@ -10,14 +10,7 @@ resources:
 - secrets.yaml
 - iscsi.yaml
 - gentoo-storage.yaml
-
-configMapGenerator:
-- name: ssh-known-hosts
-  namespace: jenkins-jobs
-  files:
-  - ssh_known_hosts
-  options:
-    disableNameSuffixHash: true
+- ../ssh-host-keys
 
 patches:
 - patch: |