add Landau-Lifschitz-Gilbert (LLG) simulation to magnetization module

[friweber]

add a new LLG class to the magnetization module which also provides a magneto-elastic coupling.

[friweber]

I added the LL class where the shared functions of LLG and LLB are in. Than I added the LLG class. Running example is provided in the .ipynb

[dschick]

Hi @friweber ,

thanks for the PR! Before going into detail, there are a lot of files which have changed in your commits (in total 21).
Somehow you have made alot of changes which are not relevant to the actual LLG simulation.

Could you please try to revert this and only have the relevant changes in your PR?

Best

Daniel

[friweber]

Now it should be better. I don't understand why it shows a difference in upload-to-pypi.yml but all other issues are resolved