Refactor - StoneyDSP Library

[nathanjhood]

The existing implementation is still a little messy; previous attempts at improving things within the codebase have lead to some complexity that is probably not necessary, given that the project is mostly just academic in nature.

Moreover, I've gotten to grips with making API's and modules with C++ and CMake in graceful ways that should now allow me to build my own library/extension for JUCE.

My intention therefore is to begin parting out the relevant source code for modularisation. This is already somewhat considered in some of the design aspects of the C++ used code, but there is currently no larger library or framework supplying these files to (potential) consumers.

The C++ module code shall be supported by a possibly optional CMake API, designed to provide consumers with easy CMake targets to link with in their projects, allowing them to easily pull in the C++ modules from various sources such as vcpkg, or even have system installations of the library, with which to build.

Furthermore, the proposed work would also allow some scope for the creation, development, and testing of a custom vcpkg registry from which the modules could be supplied.

Ideally, this external project should be able to do a CMake find_package(StoneyDSP 1.0.0 CONFIG REQUIRED) and then a target_link_libraries(Biquads PRIVATE stoneydsp::stoneydsp_audio stoneydsp::stoneydsp_graphics), and then only require the standard ProcessBlock() and MainComponent from the JUCE audio plugin template.

I have begun work on the library itself, and will be using this project as a test/example of the library.