Update dotfiles and refactor post-install scripts
Since the last commit, many of these dotfiles got a bit outdated, and I also found some pain points with my custom install scripts.
Thus, this merge request:
- Updates essentially all dotfiles by simplifying them and removing deprecated options
- Refactors my custom post-install scripts to be clearer and provide more helpful output
- Adds an install task to download the Iosevka Term SS04 font to be used in the terminal
- Simplifies the README, especially the installation instructions