Add vertical cone heading for sound emitters

Developing sounds for A32NX and I have multiple times ran into an issue of not
being able to orient the sound emitter vertically as this would make sounds
like fuel pumps, AEVC fans etc. much better positioned in sound space and
easier to get sounding right. Right now only the azimuth (horizontal
orientation) can be defined for sound emitters with “CONE_HEADING” parameter
in sound.xml. It would be great if the emitter could also be oriented
vertically with implementation of a parameter like “CONE_HEADING_VERTICAL”.
Implementation of this needs to be done on sim level and it has nothing to do
with wwise because it is defined in sound.xml. It’s the same as what we
already have available horizontally but just needs to be flipped to vertical
axis. It would help all developers get better sounds while also saving some
time now lost to getting workarounds sounding reasonably realistic.