separate locals from config values

[aks-]

Keeping a separate namespace so that what's sent per-request is separate from long-lived configuration values.

[aredridel]

Oh, this is interesting, and super useful for the namespace collisions that have bothered users of adaro.

[dougwilson]

As this is not backwards-compatible, it would have to wait for 5.0. I'm not against this at all, just highlighting why it won't get merged right away :) I'm a +1 for this, though.

[aredridel]

That's awesome. The mashed-up namespaces there really do make backward compatibility a pain -- you can't safely add anything. Separating locals is the best start.

[aks-]

Aha, thank you folks!

[wesleytodd]

I think the remaining things we need to do to land this are:

1. A deprecation warning landed in 4.x for a key named locals for render
2. Docs updates to address this change both in the upgrade instructions and in the docs for this method
3. Tests

I know we are resurrecting a PR from 2015 here, so I dont expect folks here to volunteer, but if you want to work on this please volunteer soon. I will circle back this weekend and if no one has stepped up I will try and knock out these items.

[wesleytodd]

Hey, I am guessing the folks in this PR are not interested in helping get this over the finish line at this point. Totally understandable, but also I think it means we are going to kick the can to v6 on this. We have limited contributor time and want to ship v5 asap so if we cannot get assistance landing these we are unable to get to them all. I hope we can change that in the future and start landing things more quickly for v6 and beyond.