Feature: Max-relative entropy for quantum channels

[vprusso]

Implement a function that calculates the max-relative entropy for quantum channels.

The functionality for this should be created in channel_props/max_relative_entropy.py with corresponding unit tests found in tests/test_channel_props/test_max_relative_entropy.py. Be sure to also update the docs in /docs/channels.rst under "Properties of Quantum Channels" with toqito.channel_props.max_relative_entropy.py.

For a definition of max-relative entropy for quantum channels, consult: https://arxiv.org/abs/1907.06306

See related tasks: Min-relative entropy (quantum states): #40 Max-relative entropy (quantum states): #41 Min-relative entropy (quantum channels): #42