Add get_card_by_name like source/sink

[pvizeli]

That is usefully and allow to get an card by name without loop over the full list.

[mk-fg]

I think you forgot to add type-info wrapper for C function to _pulsectl there, but I've added it in 3225ebd along with pulse.get_card_by_name(), same as in PR.

These names seem to be generated from hardware bus connection numbers, e.g. alsa_card.pci-0000_00_14.2 here, so probably bit hard to predict in advance, but guess easy to specify in various config files that way.

Thanks!