Remove aggregator module from core

[jenlampton]

I'd like to propose that we remove aggregator module from core. I suspect that is not used on 80% of all Drupal sites. To date, I have only used it a handful of times, most of those it was eventually replaced with feeds (or FeedAPI back in D6) anyway.

I'd love to hear what others think about this proposal. Is aggregator module worth keeping around?

See also: #7

[DirectorHaas]

Agreed to removal. Yes, Feeds is preferred in any reasonably complex case. Small is beautiful.

[quicksketch]

Back when we were trimming core in #7, I advocated for keeping Aggregator. However, after months of maintenance on it and the amount of enthusiasm keeping it is low, I agree we should remove it as well. Like other modules, I'd like to see this "contrib-ized", but for now taking it out so we don't have to manage it sounds like a good move to me.

@jenlampton filed a PR at backdrop/backdrop#184, which I've merged in. Thanks!

[oadaeh]

I think it would be a good thing to reference documentation on how to "contrib-ize" a core module when removing it. That would make it easier for someone to pick up the gauntlet on a task like this.