cloud/shepherd: move ssh client to own package

Change-Id: I56ad16f8f2f355243c5c0414656bbfbbff1faef5
Reviewed-on: https://review.monogon.dev/c/monogon/+/2791
Reviewed-by: Serge Bazanski <serge@monogon.tech>
Tested-by: Jenkins CI
diff --git a/cloud/shepherd/manager/BUILD.bazel b/cloud/shepherd/manager/BUILD.bazel
index 4119ff7..aa61caa 100644
--- a/cloud/shepherd/manager/BUILD.bazel
+++ b/cloud/shepherd/manager/BUILD.bazel
@@ -9,7 +9,6 @@
         "manager.go",
         "provisioner.go",
         "recoverer.go",
-        "ssh_client.go",
         "ssh_key_signer.go",
     ],
     importpath = "source.monogon.dev/cloud/shepherd/manager",
@@ -21,8 +20,8 @@
         "//cloud/bmaas/bmdb/model",
         "//cloud/shepherd",
         "//go/mflags",
+        "//go/net/ssh",
         "@com_github_google_uuid//:uuid",
-        "@com_github_pkg_sftp//:sftp",
         "@io_k8s_klog_v2//:klog",
         "@org_golang_google_protobuf//proto",
         "@org_golang_x_crypto//ssh",
@@ -47,6 +46,7 @@
         "//cloud/bmaas/bmdb/model",
         "//cloud/lib/component",
         "//cloud/shepherd",
+        "//go/net/ssh",
         "@com_github_google_uuid//:uuid",
         "@io_k8s_klog_v2//:klog",
         "@org_golang_x_time//rate",