Spring cleaning

[klappradla]

Some spring cleaning 🧹

• Clean up Brewfile: remove unnecessary packages and comments
• Remove vim markdown preview alias - I have maxdown now @pmeinhardt 💚
• Update asdf install script to always update asdf after installation
• Update script output to be less in your face
• Remove unnecessary file extensions for scripts
• Rename symlink scripts to link
• Format Markdown with prettier and add lint script
• Remove nvim plugin directory from gitignore - plugins are installed into ~/.local
• Update submodules