modernize repo

Hi, as the maintainer of [AlgoTeX](https://github.com/TUDalgo/AlgoTeX) which builds upon this project, i'd like to contribute some of the features back into upstream, as i will likely no longer be able to maintain AlgoTeX in this capacity after this semester. This PR focuses mainly on general repository improvements rather than LaTeX-features. This PR will feature: - [X] editorconfig - [X] latexindent settings - These might need improvements, as they mess up a few times - [X] pre-commit config - [X] improved gitignore - [X] default settings for vscode - [x] dockerfile - [ ] ~devcontainer to make working locally easier~ - [x] github check action - [x] github docker build action - [ ] ~possibly: action for automated ctan publishing~ - [ ] ~possibly: nix flake~ I will finish this PR in the coming weeks.