[FEATURE REQ] Generalize QNN to n qubits

[SashwatAnagolum]

Is your feature request related to a problem? Please describe.
The QNN currently only works with 2 qubits and 4 dimensional data. We need to generalize it so that it works for an arbitrary number of qubits.

Describe the solution you'd like
The ideal solution would consist of:

• Reworking the encodeData and convertDataToAngles functions using this tutorial on encoding probability distributions: we need to replace the distribution and region boundaries with the data vector, which represents the square roots of the probabilities, and perform the rest of the processing as is.
• Generalizing the circuit creation and gradient computation functions used: currently most functions are built to work with only two qubits.

Describe alternatives you've considered (if any)
None

Additional context
None