Module enabling / task workflow design [#411414]

I'm splitting this off from #407022: Show help and configuration links when modules are enabled. following discussions in #drupal-dev, #drupal-usability and elsewhere about how to improve the workflow for user interface issues.

We decided to try separating design and prototyping review from actual code review of patches - since having those discussions cross-posted on one issue can make it very hard to keep track of. So here's a rough outline of how it'll hopefully work. These aren't really ground rules, but i've posted them at such rather than trying to summarise 2-3 hours of discussion:

1. This issue will not have any patches posted to it, instead it's for high-level design and architecture discussion/prototyping. If you can't resist writing a patch, open a new issue for it, post the patch there, mark it postponed against this one (if it's directly affected).

2. Instead of posting patches, please post wireframes / screenshots / demos etc.

3. We'll use/abuse the usual core issue status - active, needs review, needs work, rtbc, fixed. RTBC means "ready to be coded", Fixed would mean (provisionally) webchick/Dries has signed off and the implementation issue is under way.

4. Once the implementation issue is happening, if someone wants to revisit major areas of the design we'll re-open discussion here to keep context.

Separating the issues doesn't mean separating anything else about the process - it's just a variation on breaking big patches into smaller ones.

If it's a complete disaster, we didn't lose much.

So the idea is that we discuss how to fix the problem of 'where do you go/what do you do after enabling a module' here and setting on a way forward, leaving the other issue for just the drupal_set_message() which is a very small change.

Other places the same problem has been discussed with different proposals for fixing it #230059: Allow modules to provide optional configuration profiles (e.g., for use in a "setup wizard") (hook_configuration())

http://groups.drupal.org/node/10919 (inline permissions changing direct from admin/build/modules)

The activity log patch currently gives us a generic A - log - B route for many different tasks. Bojhan's expressed concerns with this since clearly A - B would be better. I think we might be able to do A - B using a tasks/activity API if presentation is dealt with.