Produce qa-dep in machine-readable format (JSON)

[costateixeira]

For some IGs, it is interesting to see which other IGs depend on it. This can be used for simply identifying the dependencies, and for pkanning changes (e.g. know what IGs would be impacted with changes to a National base profile".
With some navigation and additional logic (and content?) we could do filters like showin the status of the downstream IGs, their jurisdiction and language(s), how many releases they had...

Ideally we would have some other system consuming this, not necessarily just a page in the IG.
For this, it'd be great to have the json equivalent of qa-dep.html