Port Main.DSP to MainSettings

[malleoz]

While trying to work on adding audiodump support for CLI, I was alerted that it was important to first try moving the DSP configs to the new OnionConfig before continuing, as that makes it substantially easier to write clean code to add such a feature.

This PR aims to allow for Dolphin to only rely on OnionConfig for DSP-related settings.

I am not very familiar with the new config, so please let me know if I missed any concepts in this PR. Notably, I was unsure what to do in BootManager.cpp BootCore() in the case of netplay... Seems like it uses its own SConfig which checks for DSP JIT.

[JosJuice]

Also, the new config system is not officially called OnionConfig. But this is just me being opinionated and not something that necessarily should block the PR :)

[malleoz]

Implemented Jos's review notes. Kept MAIN_DSP_HLE in Core so as to not break previous config files, finished porting over DSP HLE to use the new config, removed references to the new config from ConfigCache, and ported over MAIN_DSP_THREAD too.

[leoetlino]

Reviewed 26 of 26 files at r1, all commit messages.
Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @malleoz)

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Source/Core/AudioCommon/CubebStream.cpp, line 39 at r1 (raw file):

    return false;

  m_stereo = !Config::Get(Config::MAIN_DPL2_DECODER) || Config::Get(Config::MAIN_DSP_HLE);

Can we avoid duplicating this check? We could easily have a Config::ShouldUseDPL2Decoder that does the same thing as the existing SConfig::ShouldUseDPL2Decoder.

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Source/Core/Core/Config/MainSettings.cpp, line 142 at r1 (raw file):

const Info<bool> MAIN_AUDIO_MUTED{{System::Main, "DSP", "Muted"}, false};
#ifdef _WIN32
const Info<std::string> MAIN_WASAPI_DEVICE{{System::Main, "DSP", "WASAPI"}, "Default"};

The config key should be WASAPIDevice.

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Source/Core/DolphinQt/Settings/AudioPane.cpp, line 285 at r1 (raw file):

  if (selection != backend)
  {
    backend = selection;

This should be a Config::SetBaseOrCurrent call. (Notice that backend was a reference in the previous version of the code.)

[malleoz]

Applied the requested changes from @leoetlino. For the AudioPane.cpp line 285 fix, I wasn't sure if it was better to get rid of backend and just use Config::Get() each time, or leave it how it is such that backend is re-used for if statement on line 302. If one way is preferred over the other, let me know!

[leoetlino]

Reviewed 12 of 12 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @malleoz)

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Source/Core/AudioCommon/CubebStream.cpp, line 39 at r2 (raw file):

    return false;

  m_stereo = Config::ShouldUseDPL2Decoder();

Should be !Config::ShouldUseDPL2Decoder()

[malleoz]

@leoetlino thanks for catching that, fixed!

[leoetlino]

Reviewed 1 of 1 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @malleoz)