go/oasis-node/cmd/debug: Add the dumpdb command

This command will attempt to extract the ABCI state from a combination
of a shutdown node's on-disk database and the genesis document currently
being used by the network, and will write the output as a JSON formatted
genesis document.

Some caveats:

* It is not guaranteed that the dumped output will be usable as an
  actual genesis document without manual intervention.

* Only the state that would be exported via a normal dump from a running
  node will be present in the dump.

.changelog/2359.feature.md

@@ -0,0 +1,14 @@
+go/oasis-node/cmd/debug: Add the `dumpdb` command
+
+This command will attempt to extract the ABCI state from a combination
+of a shutdown node's on-disk database and the genesis document currently
+being used by the network, and will write the output as a JSON formatted
+genesis document.
+
+Some caveats:
+
+- It is not guaranteed that the dumped output will be usable as an
+  actual genesis document without manual intervention.
+
+- Only the state that would be exported via a normal dump from a running
+  node will be present in the dump.

go/oasis-node/cmd/debug/debug.go

@@ -7,6 +7,7 @@ import (
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/byzantine"
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/consim"
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/control"
+	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/dumpdb"
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/fixgenesis"
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/storage"
 	"github.com/oasislabs/oasis-core/go/oasis-node/cmd/debug/txsource"
@@ -25,6 +26,7 @@ func Register(parentCmd *cobra.Command) {
 	fixgenesis.Register(debugCmd)
 	control.Register(debugCmd)
 	consim.Register(debugCmd)
+	dumpdb.Register(debugCmd)
 
 	parentCmd.AddCommand(debugCmd)
 }