Flexible model loading

[faroit]

Currently the model parameters set globally when loading the lib. This makes changing the parameters when loading a new model a little bit cumbersome.

Therefore we should allow to load a model and also pass its parameters. The following ones are necessary:

// Fourier Params
const FRAME_LENGTH = config.fourierParams.frameLength
const HOP_LENGTH = config.fourierParams.hopLength
const FFT_SIZE = config.fourierParams.fftSize

// MODEL input dimensions
const N_FREQUENCIES = config.modelInput.N_FREQUENCIES
const N_FRAMES = config.modelInput.N_FRAMES
const N_CHANNELS = config.modelInput.N_CHANNELS
const N_BATCHES = config.modelInput.N_BATCHES