Allow for multiple, per-repo feature freeze windows #300
Description
We currently support 2 features that quite similar, but are implemented in different ways:
- Feature freezes, which are only configurable on the top-level configuration, and we can only configure a single timespan;
- No-deploy-on-friday nudges, which can be turned off per repo, but are not configurable in terms of time span. There is already an issue open to change the latter: Make the no-deploy-nudge time window configurable. #96
Both features require adding a suffix to the merge command to get your PR merged, the former 'as hotfix', the latter 'on Friday'. As if the syntax is not already opaque enough, we also have a 'with priority' suffix that is used to bring the PR to the front of the queue.
My proposal is to merge the features, and have multiple, per-repo configurable feature freeze windows.
This allows for example to configure the whole weekend to be off limits (not just Fridays), allows per-project configuration of other feature freezes, and would allow us to scrap one of the suffixes.
To configure the feature freeze windows in a concise way, it might be nice to be able to provide them in cron or systemd datetime syntax. There should be plenty libraries to support that.
Discussed previously with @jerbaroo