Not sure that we want to keep all of this, but probably we don't need this extra wrapper object long term, and `PurpleRequestDatasheet` (once made into a `GObject`) and `PurpleRequestFieldDatasheet` could merge.
Testing Done:
Compiled only.
Reviewed at https://reviews.imfreedom.org/r/2340/
PidginandFinch:ThePimpin' Penguin IM Clients That'reGoodfortheSoul