Initial release of `ML4Science`. The code was originally developed inside the [Φ<sub>Flow</sub>](https://github.com/tum-pbs/PhiFlow) repository and split off after version `2.4`. Major changes since the split include
* Adding `math.use()` as the primary way to specify which library to use.
* Automatic backend initialization when passing backend-specific tensors.
* Unifying the neural network libraries
* Adding documentation
* Fixing various bugs