chore: convert agent stats to use a table (#6374)

* chore: convert workspace agent stats from json to table

* chore: convert agent stats to use a table

Backwards compatibility becomes hard when all agent stats are in a JSON blob.
We also want to query this table for new agents that are failing health checks
so we can display it in the UI.

* Fix migration using default values

coderd/database/queries/workspaceagentstats.sql

@@ -1,23 +1,28 @@
--- name: InsertAgentStat :one
+-- name: InsertWorkspaceAgentStat :one
 INSERT INTO
-	agent_stats (
+	workspace_agent_stats (
 		id,
 		created_at,
 		user_id,
 		workspace_id,
 		template_id,
 		agent_id,
-		payload
+		connections_by_proto,
+		connection_count,
+		rx_packets,
+		rx_bytes,
+		tx_packets,
+		tx_bytes
 	)
 VALUES
-	($1, $2, $3, $4, $5, $6, $7) RETURNING *;
+	($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) RETURNING *;
 
 -- name: GetTemplateDAUs :many
 SELECT
 	(created_at at TIME ZONE 'UTC')::date as date,
 	user_id
 FROM
-	agent_stats
+	workspace_agent_stats
 WHERE
 	template_id = $1
 GROUP BY
@@ -30,11 +35,11 @@ SELECT
 	(created_at at TIME ZONE 'UTC')::date as date,
 	user_id
 FROM
-	agent_stats
+	workspace_agent_stats
 GROUP BY
 	date, user_id
 ORDER BY
 	date ASC;
 
--- name: DeleteOldAgentStats :exec
-DELETE FROM agent_stats WHERE created_at < NOW() - INTERVAL '30 days';
+-- name: DeleteOldWorkspaceAgentStats :exec
+DELETE FROM workspace_agent_stats WHERE created_at < NOW() - INTERVAL '30 days';