Subsite-level and time-based granularity for mod actions

[csebianlander]

There are two types of potential moderator punishments/actions that right now, as far as I understand it, would have to be enforced manually through a careful review of a poster's activity:

1. Restricting a user's usage of a particular subsite, e.g. User X cannot post on MetaTalk (but can otherwise view/use the site as normal)
2. Restricting a user's usage of all or some of the site for a designated period of time (i.e. a "time out")

It'd be nice to have the moderator back-end allow for these things to be done systemically -- particularly the first, as I think this could really help de-escalate certain situations without feeling like moderators are forced into nuclear options.

@kirkaracha curious what you think is feasible as far as this goes; I'm hopeful there's some out-of-the-box ways to implement this to some degree. if not we can put this much more deeply on the backburner.

[kirkaracha]

We should be able to do both of those. I'm not sure if there's an existing package, but it doesn't seem too complicated.

[csebianlander]

let's tentatively plan to roll it out as we finalize the moderator back-end for launch -- if it turns out more complicated than it seems we can just put it on the post-launch backlog!