[FEATURE] Routing modulation signals

[jatinchowdhury18]

Is your feature request related to a problem? Please describe. Currently some processors (tremolo, chorus) use modulation signals. Currently there is no way to sync modulation signals or to use custom modulation signals.

Describe the solution you'd like Processors that use modulation signals could have an extra input and output port (probably marked with a different colour). If the input port is connected, then the signal coming in on that port will be used as the modulation signal. The ouput port will pass on the modulation signal so it can be re-used by other processors.