Add automation to prevent breaking URLs

[encukou]

(This was discussed at one of the meetings, filing an issue so it isn't forgotten.)

Any kind of reorganization can break existing URLs. Ideally any breakage is intentional rather than accidental. Even more ideally, we add some redirect mechanism.

Brian Skinn's sphobjinv library might be useful for inspecting Sphinx inventories.

[CAM-Gerlach]

Sphinx-Rediraffe, which we now use on the devguide, can also automatically check this at least at the page level.

[bskinn]

Aha, I didn't realize what you were trying to do from the comment in the meeting notes.

sphinx-rediraffe absolutely looks like what you want, not sphobjinv.