Deprecate require("brigade").bundle unless a compelling use case emerges

Minification (the main use case for bundle-level transformation) is provided automatically by the tool, and ever since cc326f09e293861240083dcbfd7ea1eb10646071 it likely makes more sense to apply build steps to individual modules whenever possible.

Please comment here if you have any reason for opposing the removal of `require("brigade").bundle`.

Start by reviewing the `require("brigade").bundle` entry point and the rationale in commit `cc326f09e293861240083dcbfd7ea1eb10646071`. Confirm whether bundle-level transformation still has a compelling use case; done means reaching a project decision on deprecating or retaining the API.

Written by the indexing model from the issue text.