feat(coderd/provisionerdserver): insert sub agent resource (#21699)

Update provisionerdserver to handle the changes introduced to
provisionerd in https://github.com/coder/coder/pull/21602

We now create a relationship between `workspace_agent_devcontainers` and
`workspace_agents` with the newly created `subagent_id`.

coderd/database/migrations/000413_add_subagent_id_to_dev_containers.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE workspace_agent_devcontainers
+	DROP COLUMN subagent_id;

coderd/database/migrations/000413_add_subagent_id_to_dev_containers.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE workspace_agent_devcontainers
+	ADD COLUMN subagent_id UUID REFERENCES workspace_agents(id) ON DELETE CASCADE;