Multiple prototool.yaml files in the same project

[amckinney]

We should consider the prototool.yaml hierarchy and determine whether or not we should stick to the current tree/override behavior. A single prototool.yaml at the project's root might be sufficient for now. This would also simplify some of the implementation details found in the settings package.

If there isn't an obvious need for the hierarchy, it might be worth deferring until after a 1.0 release.

[peats-bond]

I'm in favour of one prototool.yaml for one project and slimming down internal/settings. If there is a demand for this, we can reintroduce post 1.0. Let's not make this a 1.0 blocker, however.

[bufdev]

I think you'll want this too, but note moving to this now will lock you in later. The big thing is everywhere you see protoSets ...*file.ProtoSet and fileDescriptorSets []*FileDescriptorSet - as the code is now, it supports multiple sets of Protocol Buffer files (corresponding to multiple prototool.yaml files), and deleting that logic will make it complicated to add it back in the future (it was complicated to move to in the first place).

If you want to lock it in, that's fine too, we probably only will want a single prototool.yaml file, but just an FYI.

Note this issue is more or less a duplicate of #10.

[bufdev]

Closing this for now as we went with one prototool.yaml file, we can re-visit in the future if we need a different setup.