feat: add outbox

Signed-off-by: kjuulh <contact@kjuulh.io>

crates/crunch-postgres/migrations/20231003181849_initial.sql

@@ -0,0 +1,8 @@
+-- Add migration script here
+CREATE TABLE outbox (
+    id UUID NOT NULL,
+    metadata JSONB NOT NULL,
+    content BYTEA NOT NULL,
+    inserted_time TIMESTAMPTZ NOT NULL DEFAULT now(),
+    state VARCHAR NOT NULL,
+);