Add pre commit

As we are multiple people contributing, it makes sense to automate a few things: Namely: Running some codespell checks, adding a clang-format etc on the pre-commit hooks. A very common approach is to use: https://pre-commit.com/index.html

In this PR, I added a small pre-commit configuration, modified the clang-format to match the google Style and be compatible with the pre-commit hooks and fixed some codespell problems.