QAudioInput pulseaudio plugin sets volume system wide

When starting audio recording using QAudioInput on Linux, the pulseaudio plugin sets recording volume to 100% explicitly. Due to the nature of pulseaudio mixers, this sets the mixer volumes on most systems to a massive amount of gain, resulting in a clipped recording. It also adjusts the system volume to this level, affecting all applications.

The same behaviour is seen in audio outputs on pulseaudio, and the pulse QAudioOutput code has a workaround for this.

I have a patch ready, will submit for review and link to this bug.