m/p/cmd: implement RunCommand

This implements a new utility function RunCommand, based on existing
m/installer/test implementation.

RunCommand will be used in the upcoming metroctl test implementation.

Change-Id: Ieb98acada7e7408249da0e289861674e80b4d581
Reviewed-on: https://review.monogon.dev/c/monogon/+/789
Tested-by: Jenkins CI
Reviewed-by: Sergiusz Bazanski <serge@monogon.tech>
diff --git a/metropolis/pkg/cmd/BUILD.bazel b/metropolis/pkg/cmd/BUILD.bazel
new file mode 100644
index 0000000..7d5bbeb
--- /dev/null
+++ b/metropolis/pkg/cmd/BUILD.bazel
@@ -0,0 +1,11 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "cmd",
+    srcs = ["run.go"],
+    importpath = "source.monogon.dev/metropolis/pkg/cmd",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//metropolis/pkg/logbuffer",
+    ],
+)