Should it be possible to configure shorter namespace lifetimes than the cleanup loop checks?

[Payback159]

Describe the bug

If the namespace lifetime is smaller than cleanupInterval in the tenama configuration, the namespace may still exist longer than desired.

To Reproduce
Steps to reproduce the behavior:

1. set cleanupInterval in the tenama configuration for example to 15m
2. create namespace with a lifetime of 5m
3. wait for 5m if the loop isn't random synced with the namespace lifetime the namespace will exist after 5m

Expected behavior
I would expect that the namespace will be cleared after it's configured lifetime.

Screenshots
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Additional context

I think at the moment the problem exists because the cleanup logic is based on a timely based loop which is execute in a configureable time (in the example all 15m). Maybe we can implemented an api-watcher which get's notified when the lifetime of a namespace is reached and cleans it on a more event-based way.

Alternative we can implement that the namespace lifetime can't be smaller than the cleanupInterval but I think that would be not the best solution.