Migrate from Uptime Robot to Upptime

We've been using [UptimeRobot ](https://uptimerobot.com/) for years. At least 4 years. We've been paying $84/y but last year with their pricing change, @Popolechien got us 2y free for us being a non-profit. We have the [Solo Plan](https://uptimerobot.com/pricing/?ref=header) with 50 monitors.

It serves us correctly and we can't complain much but it's a closed, paid solutions which is not that flexible.

[Upptime](https://upptime.js.org) ([repo](https://github.com/upptime)) is a better, libre and free alternative.

The main difference, and what makes it free is that it runs on Github Actions.

- Configuration is on Github as conf file (it's all in a dedicated repo)
- Creates Github Issues for incidents
- Assigns those tickets so we're notified on GH (general assignee and per-target assignees)
- Supports external notifications (Slack, Mailgun, etc)
- Record response time as well
- Supports SSL date checks
- Supports scheduled maintenance via Issue with specific label
- Records data in the repo (commits JSON files used for graphs)
- Workflow can be triggered manually
- Supports badges (as the ones we use in repos)
- Status page is more flexible
- Status page links directly to opened tickets and so we have actual history with rich information.
- It's free software so it can be improved.

I haven't seen any UptimeRobot feature (that we'd have access to) that is not possible with it.

Please check [this status page](https://iterate-ch.github.io/upptime/) and the [config docs](https://upptime.js.org/docs/configuration) to get a sense of what it would look like.

It is important to acknowledge that we'd be depending on Github so when github pages are down, our status page would be down and when GH actions are down, there would be no updates. We're equally dependent on UptimeRobot at the moment, with less visibility.

At this stage, you should be convinced it's a no-brainer but there's an important limitation: Actions are limited to run **at most every 5mn** on GH. With our current plan on UptimeRobot, we can schedule every minute.
Related, as those are GH Actions, I've seen tickets about it not running exactly every 5mn. See [this post](https://upptime.js.org/blog/2021/01/22/github-actions-schedule-not-working/) but nobody complained after 2022 so maybe GH has just become more reliable.

I think it's easy enough to setup that we should do it, in parallel to UptimeRobot for now and see if the limit is acceptable or not. We still have a year of free service on UptimeRobot.