Fix broken checkins on static services

[jannispl]

This PR fixes some issues with the checkin feature:

• Services now come back online when a checkin is pushed (Check-in not working. statping/statping#824)
• Showing average response time does not really make sense so I removed that for static services if it would be 0
• Checkin hits are now accounted for in "Uptime last 24 hours" / "Uptime last 7 days"
• Previously checkins were checked periodically according to the interval specified in the checkin, this now also takes into account the timeout defined on the service
• The recorded checkin list would show all checkins ever recorded, I limited this to 32 (just like it happens with failures already)

There are some remaining problems with graphs remaining in 'Loading' state when there is no data (e.g. latency), but this PR should make checkins more usable for static services.

[adamboutcher]

Holy moly this looks good!

I need to properly check this and maybe convince someone else to verify but if this does fix things then you're going to make lots of people happy!

Thanks.

[aspyct]

Hello :)

I need this feature, and I'm happy to test it if that's useful :)

[fredronnv]

I'm also up for testing this feature, let me know, it would be nice to get this over the hump and merged.

[jannispl]

@adamboutcher
So frustrating to see such a widely requested feature/fix not getting enough attention from maintainers/collaborators other than "holy moly this looks good" for half a year. If this project is dead, please update your README.md accordingly, potentially asking the community for new maintainers.

This is the reason why a lot of people (including me) moved to more actively maintained alternatives, such as Uptime Kuma.

[adamboutcher]

I know it's frustrating, if someone else wants to test and verify then I'm not stopping them.

I'm eager for maintainers but we don't get any requests to be active because I expect most people are like myself and have other jobs and life getting in the way.

If anyone wants to maintain, feel free to email me adam@aboutcher.co.uk