archive/soft delete stale lists

[collinbarrett]

Support indicating lists that are archived/stale/no-longer-updated. Rather than deleting such lists, keep them on the site but indicate that they are no longer maintained in some way.

Re-opening a feature request that has been off-and-on supported/requested over the site iterations. Latest request is in #3951.

Related to #440, #182, #42, #713, #371, #44.