Big refactor for 0.2

[harudagondi]

Note

The first checklist group is only the necessary requirements to merge this PR.

The rest are not needed, but nice. It is better if the others are put in a separated PR.

Objective

• This is a very big refactor that allows better ergonomics, better refactorability, and better support for streaming audio.
• Partially complete Add support for streaming DSP graphs #1 for bevy_audio,
  • [Merged by Bors] - Remove Sync requirement in Decodable::Decoder bevyengine/bevy#5819 needs to be merged first. is now merged! Now waiting for bevy 0.9.
  • Support playing sounds that implement kira's SoundData NiklasEi/bevy_kira_audio#63 is blocking for kira.
• Partially complete Allow support for setting parameters #2 for oddio
  • Add equivalent to kira's Handle or oddio's Controlled in bevy_audio::Decodable bevyengine/bevy#5828 needs to be resolved first
  • Support playing sounds that implement kira's SoundData NiklasEi/bevy_kira_audio#63 is blocking for kira
  • oddio isn't even implemented yet for this PR
  • By virtue of solving Allow support for setting parameters #2, then Add integration with midi #3 will be unblocked
• Unblocks Allow parametization of DSP graph functions #4 by using DspGraph
• Fixes Add support for bevy_oddio #5

Solution

• Add support for
  • bevy_audio, blocked by [Merged by Bors] - Remove Sync requirement in Decodable::Decoder bevyengine/bevy#5819 Now waiting for bevy 0.9.
  • bevy_kira_audio, blocked by Expose several types NiklasEi/bevy_kira_audio#72 Now waiting for bevy 0.9.
  • bevy_oddio
• Add support for streaming audio in
  • bevy_audio, blocked by [Merged by Bors] - Remove Sync requirement in Decodable::Decoder bevyengine/bevy#5819
  • bevy_kira_audio, blocked by Support playing sounds that implement kira's SoundData NiklasEi/bevy_kira_audio#63
  • bevy_oddio
• Allow setting of parameters in
  • bevy_audio, blocked by Add equivalent to kira's Handle or oddio's Controlled in bevy_audio::Decodable bevyengine/bevy#5828
  • bevy_kira_audio, blocked by Support playing sounds that implement kira's SoundData NiklasEi/bevy_kira_audio#63
  • bevy_oddio

Note for Users of this Branch

If you are a user of bevy_fundsp, please try to test this PR! This currently only works with bevy_audio (EDIT: and bevy_oddio!), because this relies on a branch I made on bevy.

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Changelog

Reworked the majority of the code.

Added

• A way to play streaming DSP sources. See SourceType::Dynamic.
• You can play DSP sources using Audio::play_dsp.
• Two iterators on streaming audio sources: Iter and IterMono.

Changed

• Adding the DSP plugin.
  • You must now call DspPlugin::default().
• The method on adding DSP sources.
  • No more initializing using DspAssets!
  • Just add your DSP function using app.add_dsp_source
• Playing DSP sources require Audio to be mutable. (Use ResMut)
• A lot of internals are shuffled around.

Removed

• DspAssets
• FnDspGraph
• StreamingDspSource