Iterate through positional audio program names only once

Context

Right now Mumble iterates through every program name of every PID for every positional audio plugin. This is quite wasted CPU time if either the PID count is high or plugin count is high, as the time complexity is in $\mathcal{O}(PIDNum \cdot pluginNum )$.

Example: https://github.com/mumble-voip/mumble/blob/dd5df45313a937359285327f556557159bab758e/plugins/gtav/gtav.cpp#L81

Description

A better solution would be if each plugin tells Mumble what program name it is looking for, so that only Mumble has to iterate over the PID-list once.

Mumble component

Client

OS-specific?

No

Additional information

This issue originated from https://github.com/mumble-voip/mumble/pull/5704#issuecomment-1141938952