Add white, pink, brown noise dsp

[tong]

Not sure if you want aura to be just game related or have any dsp filters, effects, generators, … I do have some webaudio stuff around like these noise generators which might be nice to have.

[tong]

btw: here https://disktree.net/app/noisegen/ are these noise generators as html5 audioworklet version (source: https://github.com/disktree/noisegen).

[MoritzBrueckner]

Awesome, thanks! I'm totally fine with adding noise generators, they might be helpful in some situations.

However I have a few open questions before merging:

• Even though they probably count as DSP, the current noise generators are more generators than effects, but the DSPs are currently all used as insert effects (effects that work on the output signal of the channel they are linked to, compared to "send effects" which aren't implemented yet). The noise generators in this PR seem to completely override the buffers so I'm wondering if they should be channel classes instead (maybe in a oscillator or generator subpackage)? Currently you'd have to load a sound if you want to play just noise.
• The generators currently are not really mono and not really stereo but something in between: last and the bX variables are used from the last sample if I'm not mistaken, but in Kha the buffers are interleaved, meaning that there is always a left sample, then a right sample, and so on. It could make sense to use preallocated left/right vectors instead to get a real stereo noise (if that's wanted).

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Btw, I'm planning to eventually add a html5 backend that works with the webaudio API as much as possible and maybe even with worklets for better performance, however that might take a while and I wasn't able yet to hear any sound when using the webaudio API with Aura (although the html5 backend in Kha works just fine...)

[tong]

Allr8, maybe you can integrate this with desired changes.

I think worklets should be used by kha itself, but i am not sure if and how that fits all together. For sure is that we want to have a dsp graph (nodetree) in armory like unreal metasounds at some point, maybe something to consider when changing the aura api.