cloud/bmaas/bmdb: init

This adds the initial Bare Metal Database structure. This change focuses
on a session/work mechanism which is the foundation on which we will
build worker components. It allows lease-like mechanics on machines,
letting us not have to use 'standard' work queues in the BMaaS project.

Change-Id: I42c3f4384c64fd90dbeab8ff9652a6f611be81d4
Reviewed-on: https://review.monogon.dev/c/monogon/+/953
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql
new file mode 100644
index 0000000..6a85991
--- /dev/null
+++ b/cloud/bmaas/bmdb/model/migrations/1662136250_initial.down.sql
@@ -0,0 +1,6 @@
+DROP TABLE machine_agent_report;
+DROP TABLE machine_agent_installed;
+DROP TABLE machine_provided;
+DROP TABLE work;
+DROP TABLE sessions;
+DROP TABLE machines;