[Refac] Add pyq noise

[EthanObadia]

This issue includes several tasks for refactoring and adding noise in Qadence:

Merge run and run_dm in the backends:

• Remove the run_dm method from the abstract class Backend, the Horcrux, Bracket and Pyqtorch classes..
• Merge the run_dm and run methods in the Pulser backend class.
• Modify the unpyqfy method to represent the output density matrix as tensor.
  Closes [Feature] Enable noisy simulations through run() #428

Add the noise gates from pyq:

• Add an optional noise parameter to the PrimitiveBlock class
• Add an optional noise parameter to the ParametricBlock class
• Update the Primitive and Parametric block instances class to support the noise attribute.
• Add pyq's protocols to the Noise Class.
• Modify the convert_block function:
• Add a constructor in pyq:
  Closes [Proto] Integrate the Pyqtorch's noisy simulation #423

Add the noise features:

• Create a function to add a noise protocol after every gate in a circuit.
• Create a function to add a noise protocol after a specific type of gate in a circuit.
  (Will open an issue)

[dominikandreasseitz]

came here to suggest this, nice that you spotted it already @EthanObadia