Add Support for CLAP Plugins

[Glenn 'devalias' Grant]

It would be useful to have CLAP plugin support in Pedalboard. Right now, we can't any plugins that only come as CLAP.

• https://u-he.com/community/clap/

  • CLAP: The New Audio Plug-in Standard
    Bitwig and u-he are excited to announce CLAP (CLever Audio Plug-in API), the new open standard for audio plug-ins and hosts. CLAP offers modern features, innate stability, and rapid support for plug-in and host developers. And since it's open source and liberally licensed, CLAP is a safe bet for the future.

Based on what I read in #240, it seems Pedalboard is mostly based around JUCE for plugin loading.

Doing some googling lead me to the following resources:

• https://forum.juce.com/t/fr-support-clap-for-plugins-host-client/51860

  • FR: Support CLAP for plugins (host & client)

• https://github.com/free-audio/clap-juce-extensions

  • JUCE6 and 7 Unofficial CLAP Plugin Support

    This is a set of code which, combined with a JUCE 6 or JUCE 7 plugin project, allows you to build a CLAP plugin. It
    is licensed under the MIT license, and can be used for both open and closed source projects.

    We are labeling it 'unofficial' for four reasons

    1. It is not supported by the JUCE team,
    2. There are some JUCE features which we have not translated to CLAP yet,
    3. It presents a set of completely optional extensions which break JUCE abstractions to allow extended CLAP feature
       support and
    4. It does not support JUCE-based CLAP hosting

Based on these, it sounds like JUCE doesn't currently support hosting CLAP plugins, even with the extension linked above.

See Also

• #240
• #269