feat: allow specifying devcontainer on agent in terraform (#16997)

This change allows specifying devcontainers in terraform and plumbs it
through to the agent via agent manifest.

This will be used for autostarting devcontainers in a workspace.

Depends on coder/terraform-provider-coder#368
Updates #16423

coderd/database/queries/workspaceagentdevcontainers.sql

@@ -0,0 +1,20 @@
+-- name: InsertWorkspaceAgentDevcontainers :many
+INSERT INTO
+	workspace_agent_devcontainers (workspace_agent_id, created_at, id, workspace_folder, config_path)
+SELECT
+	@workspace_agent_id::uuid AS workspace_agent_id,
+	@created_at::timestamptz AS created_at,
+	unnest(@id::uuid[]) AS id,
+	unnest(@workspace_folder::text[]) AS workspace_folder,
+	unnest(@config_path::text[]) AS config_path
+RETURNING workspace_agent_devcontainers.*;
+
+-- name: GetWorkspaceAgentDevcontainersByAgentID :many
+SELECT
+	*
+FROM
+	workspace_agent_devcontainers
+WHERE
+	workspace_agent_id = $1
+ORDER BY
+	created_at, id;