m/{cli,test/launch}: integrate launch/cluster with metroctl

This makes test-launch2 (and possibly later any other code that uses the
launch/cluster library) tell the user that they can connect to the newly
launched cluster using metroctl, either by using specific flags, or
using a wrapper script, or using kubectl.

Change-Id: I54035ee02f3cbab3d17f46b1f1685b91aab275a9
Reviewed-on: https://review.monogon.dev/c/monogon/+/1373
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/go.mod b/go.mod
index ff2d8ed..37b8525 100644
--- a/go.mod
+++ b/go.mod
@@ -92,6 +92,7 @@
 	github.com/improbable-eng/grpc-web v0.15.0
 	github.com/insomniacslk/dhcp v0.0.0-20220119180841-3c283ff8b7dd
 	github.com/joho/godotenv v1.4.0
+	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
 	github.com/kevinburke/go-bindata v3.23.0+incompatible
 	github.com/kyleconroy/sqlc v1.15.0
 	github.com/lib/pq v1.10.6