Test WinSCP

This commit adds support to discover garage instances running in
kubernetes.

Once enabled by setting `kubernetes_namespace` and
`kubernetes_service_name` garage will create a Custom Resources
`garagenodes.deuxfleurs.fr` with nodes public key as the resource name.
and IP and Port information as spec in the namespace configured by
`kubernetes_namespace`.

For discovering nodes the resources are filtered with the optionally set
`kubernetes_service_name` which sets a label
`garage.deuxfleurs.fr/service` on the resources.

This allows to separate multiple garage deployments in a single
namespace.

the `kubernetes_skip_crd` variable allows to disable the creation of the
CRD by garage itself. The user must deploy this manually.

@@ -40,3 +40,3 @@
 
 pub const BACKGROUND_WORKERS: u64 = 1;
-pub const BACKGROUND_TRANQUILITY: u32 = 3;
+pub const BACKGROUND_TRANQUILITY: u32 = 2;

@@ -563,0 +575,4 @@
+				if let Some(ec) = self.resync_errors.get(hash.as_slice())? {
+					let ec = ErrorCounter::decode(ec);
+					if now < ec.next_try() {
+						// if next retry after an error is not yet,