Only match RSS rules once or on a schelude

[enoch85]

Taken from here: Flood-UI/flood#752

It would be nice to only match RSS rules once, like in ruTorrent where you can choose "minimum interval" and then have a dropdown which let's you choose:

- always match
- only match once
- 1 day
- 2 days
- 4 days
.....
- 1 month

The reason is that you don't want every single release of a torrent, it's sufficient with one version, and on a schedule if there are frequent releases let's say every week or so.

I don't know if this already is a part of Flood-UI/flood#633?