Bug 2365811

Cron packages, like cronie, need to add `Provides: cron` (and `Provides: anacron` as needed) to themselves.

AND packages like "crontabs" need to `Requires: cron` rather than a specific implementation like cronie.

This allows any cron implementation to be installed on fedora, without hacks like `Provides: cronie` in alternate packages.

This would allow seamless interchanging of various cron implementations...

Additionally, the "crontab" binary needs to be interchangeable via "update-alternatives".

Reproducible: Always

Steps to Reproduce:
No specific steps... It's a package metadata issue.
Actual Results:
- Alternate cron implementations need to either re-implement the entire "crontabs" package or if they depend on it need to `Provides: cronie` in order to avoid pulling the redundant cronie daemon, which if running may re-run the crobjobs which are already taken care of by the alternate implementations.
- `crontab` binary is different across implementations, and conflicts when multiple cron impelmentations are to be installed... Any implementation has to depend on "crontabs" which depends on cronie, and there is a conflict with the alternate implementation of `crontab` binary.

Expected Results:
- Installing any alternate cron implementation should be seamlessly supported as anything needing cron has `Requires: cron`. Without hacks or needing to account for other specific implementations.
- "crontab" binary should be interchangeable via "update-alternatives".

Additional Information:
https://bugzilla.redhat.com/show_bug.cgi?id=2350109

This is a cron implementation which is a systemd generator rather a traditional cron daemon; It generates systemd service-timer unit pairs for each cronjob, which systemd runs.

Trying to package this, in a clean way such that it is interchangeable and drop-in replacement to cronie, the problem becomes apparent.