m/installer/install: move from osbase/build/mkimage/osimage

Move the package osbase/build/mkimage/osimage to
metropolis/installer/install. The package contains "metropolis" in
various strings, so it fits better in //metropolis than in //osbase.
The parent package mkimage no longer exists.

The rename also removes the name clash with osbase/oci/osimage.

Change-Id: Ia228ab94c937f4c7a5b6eb1fcc77993a594d64b6
Reviewed-on: https://review.monogon.dev/c/monogon/+/4296
Tested-by: Jenkins CI
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
diff --git a/cloud/agent/BUILD.bazel b/cloud/agent/BUILD.bazel
index 48e7d20..a25ea38 100644
--- a/cloud/agent/BUILD.bazel
+++ b/cloud/agent/BUILD.bazel
@@ -14,11 +14,11 @@
     visibility = ["//visibility:private"],
     deps = [
         "//cloud/agent/api",
+        "//metropolis/installer/install",
         "//metropolis/node/core/devmgr",
         "//metropolis/node/core/network",
         "//osbase/blockdev",
         "//osbase/bringup",
-        "//osbase/build/mkimage/osimage",
         "//osbase/efivarfs",
         "//osbase/net/proto",
         "//osbase/nvme",