[Documentation] Adding noisy simulation documentation

[sungwoo-pasqal]

Raising an issue to improve documentation of noisy simulation.

--- Contents to be added ---

• How to use Digital/Analog noise in qadence blocks (BitFlip, Depolarizing, NoiseHandler, etc)
• Rearrange documentation of noise section in contents and tutorials
• Show code examples and results of applying noise
• Show different granularity of noise application to the circuit

Please add comments or helpful links to this issue. @jpmoutinho @RolandMacDoland

[jpmoutinho]

Thanks @sungwoo-pasqal. The bulk of the current information seems to be in the simulated errors tutorial: https://pasqal-io.github.io/qadence/latest/tutorials/realistic_sims/noise/

Most of it probably belongs in a page in the Contents section. Like you said, probably missing is the interface for the different granularity, e.g. adding it at the gate level, circuit level, model level.