Replace crate prometheus with prometheus-client

[MrCroxx]

RisingWave initially chose the crate prometheusas the client for Prometheus because of its convenience. However, as the system became more complex, the flexibility of crate prometheus brought a lot of burden to the maintenance of metrics.

• feat(batch): improve the implementation of BatchTaskMetrics #5770
• fix(batch): remove task metrics after task finishes and ensure metrics are collected #9171
• fix(metrics): clean streaming actor metrics after dropped (p1) #9756
• feat(log-store): add metrics for log store #12653
• feat(metrics): support reference counting in metrics label #12882
• feat(metrics): remove metrics labels after being collected #13080

Besides, prometheus is not actively maintained now.

tikv/rust-prometheus#490

Now, prometheus has its official rust client crate prometheus-client, which gives less flexibility but makes it easier to maintain. It's time to explore the official crate and replace prometheus with prometheus-client.

[github-actions]

This issue has been open for 60 days with no activity. Could you please update the status? Feel free to continue discussion or close as not planned.

[xxchan]

brought a lot of burden to the maintenance of metrics.

Would you mind elaborating what's the pain point? 🤔

[MrCroxx]

brought a lot of burden to the maintenance of metrics.

Would you mind elaborating what's the pain point? 🤔

This is a description before we have label guarded metrics. I tried to implement it in a clearer way, which required some tiny modifications to the upstream prometheus crate. But the crate was not in good maintain status. The PR was merged but no new version released (even till today).

Thankfully, Yiming made an implementation without requiring modifications to the upstream.

[MrCroxx]

However, tikv/rust-prometheus is in a bad maintenance state, although there is not much to maintain.

FYI: tikv/rust-prometheus#530