Update notebooks to newer Python version and to use RoughPy

[rchan26]

Most of the notebooks were created a 2/3 years ago using older versions of various libraries and Python versions. Additionally, most use esig or iisignature for signature computation, so we can update this to use RoughPy instead.

• MNIST example (Update MNIST example #9)
• NLP example (Update NLP example #10)
• Drone identification example (Update drone identification example #11)
• Human action recognition example (Update human action recognition #12)
• Controlled NDEs example (Update controlled neural differential equations example #13)
• Sepsis detection example (Update sepsis detection example #14)
• Anomaly detection example (Update anomaly detection example #15)