Proof of Service changes and sundries

[ekressmiller]

Proof of service work, closes #203:

• simplify order proofs of service by just keeping order and POS in same PDF, the way they come from the state. This way we don't need to use logic to recombine them.
• change existing proof of service objects and logic to be for the petition POS instead (and rename POS objects to make it clear they are for the petition versions). Enable petition POS only if not ex parte and not Wayne.
• adjust order in which docs display on download screen
• stop adding parents names to minor proof of service forms to match LHI (and because we don't know which parent will be served)

Other changes:

• stop excluding certain counties from wants_other_request, closes #204
• fix pet/resp relationship bug introduced by 1c1cebaf2d949b585216666abd8036c892fa093f

[ekressmiller]

@RamiLorca, some context you may not have been given along the way is that there are 2 different types of proof of service involved (3 if you count the one that comes with the notice of hearing, but we can ignore that here):

1. for the petition (which is only needed if it's NOT ex parte) and
2. for the order itself, which I believe we always want except for Wayne.

Anyway, I realized we were using logic to recombine PDFs for the orders and their accompanying proof of service when we could just treat them as a single PDF from the very beginning (in fact, they come that way from the state). So I made that change, and used the proof of service infrastructure in the code for the petition proofs of service instead, with some adjustments.