Support for ingest namespacing

Move content status to list statuses and add single status
to interface.
Updates API to support list statuses and status
Updates snapshot key creation to be generic

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

content/content_test.go

@@ -52,7 +52,7 @@ func TestContentWriter(t *testing.T) {
 	}
 
 	// we should also see this as an active ingestion
-	ingestions, err := cs.Status(ctx, "")
+	ingestions, err := cs.ListStatuses(ctx, "")
 	if err != nil {
 		t.Fatal(err)
 	}