site settings: new "free project limit" numerical value. 0 disables it, or a number in minutes.
add a countdown time to the "red banner", which appears for projects without upgrades, which are older than a certain age (this PR changes one of the parameters to 15 days, instead of 30)
when the banner is at 0, it stays at 0 and closes all editors and stops the project
when you click on the countdown, you get a dialog explaining the situation – similar to wikipedia
STATUS: what's left to do is testing and thinking through the logic, but overall I think this is ready to go
Description
Checklist: