[meta] Get Panopoly 1.x into maintenance mode (so we can focus on Drupal 8)

It's been our goal since the end of last year to get Panopoly 1.x for Drupal 7 into "maintenance mode" so that we can focus our energy on Panopoly 2.x for Drupal 8.

Maintenance mode means that we'll still fix bugs, update modules, make security releases, improve accessibility, add tests and do code clean-up, but we won't work on any new features or functionality changes. We'll still take regressions very seriously, and since we'll be making fewer changes in general, hopefully we'll cause fewer of them too. :-)

The goal is to keep Panopoly 1.x stable and dependable until Drupal 7 is no longer supported (probably at least 3-ish years from now), but to work on new stuff in Panopoly 2.x for Drupal 8.

I also think it's worth discussing if it makes sense to bring on a new co-maintainer or two to lead that maintenance? I know that personally, I'll be a lot less focused on Panopoly 1.x in D7 once Drupal 8 is released (which will hopefully be before the end of 2015).

Anyway, what do we need to get done before we can switch to pure maintenance mode?

(FYI, this is just my proposal -- it's still open for discussion and changes!)

Conceptually

• Fixing known critical or major bugs
  • Critical bugs = regressions!
  • Major bugs = issues that prevent a large class of users from installing or using Panopoly for one of it's core use case (ex. installation via Aegir being broken, conflicts with Bootstrap based themes, etc)
• Finishing any major Feature additions that were started before July 2014. I think only #1987386: Include Radix theme in Panopoly is left?
• Updating all bundled modules to their latest stable versions

Specifically

We're going to need to go through issues in the queue and:

1. Correctly classify any bugs as Critical or Major
2. Make this issue the "Parent issue" on any issues that meet the above criteria

Once we have the full list together, I'd like to get at least two maintainers to sign-off and say "yeah, that sounds reasonable". (But no approval is necessary to start changing issues - anyone can do that! If someone disagrees, we can just change it again! ;-))