m/n/core/cluster: rewrite bootstrap to conform to cluster lifecycle DD

This removes the existing cluster/manager code and reimplements it from
scratch, finally implementing the cluster lifecycle design document for
cluster bootstrap.

Test Plan:
E2e should cover this. Maybe we could unit test the manager? But that would
require a ton of DI work. Not sure if it's worth it.

X-Origin-Diff: phab/D735
GitOrigin-RevId: b00c97b0a102a21605d16086df82a6ece6eb7f4d
diff --git a/metropolis/node/core/cluster/configuration.go b/metropolis/node/core/cluster/configuration.go
new file mode 100644
index 0000000..adb156d
--- /dev/null
+++ b/metropolis/node/core/cluster/configuration.go
@@ -0,0 +1,19 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cluster
+
+