neonvm-runner-image-loader: Faster rollout (#923)

Specifically, this PR sets `maxUnavailable = 100%`, which allows
updating all replicas in parallel.

An issue we see during rollout is that it often takes 30+ seconds to
create a new neonvm-runner-image-loader on a node, and doing this for
many nodes takes an unreasonable amount of time. This improves that.

neonvm/runner-image-loader/daemonset.yaml

@@ -6,6 +6,10 @@ spec:
   selector:
     matchLabels:
       name: neonvm-runner-image-loader
+  updateStrategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxUnavailable: 100%
   template:
     metadata:
       labels: