FEATURE REQUEST: more flexible interval override

[thewoolleyman]

Currently, we use site checks as a "MVP CI" - e.g. we hit a "canary page" that indicates if a given site is working correctly.

However, we want these to be at a longer interval (e.g. 120 seconds), so they don't spam the server with requests.

The problem is when we add or change a site check name, all existing workstations don't have the local override for the new site name, they default to frequently checking it and spamming it.

This has a "viral" effect, of all workstations spamming as soon as they pull the new Checkfile, until the local interval override is made for the new sites.

Two possible solutions:

1. Make local interval overrides take wildcards/regex, e.g. so all site checks can be given a longer interval, regardless of their name
2. Allow interval to be overridden in the Checkfile itself, so the interval is set as soon as the new Checkfile (and new sites) are checked out.