IMPLEMENTATION: Move the implementation into a dedicated subfolde

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
IMPLEMENTATION: New implementation available - as a VST

This rely on the Juce framework, referenced here as a submodule.

Signed-off-by: Gama <misept.dieseneuf@gmail.com>
SCRIPTS: Ignoring all externals submodule

Signed-off-by: Gama <misept.dieseneuf@gmail.com>