allow to specify to be installed software outside of the script (more flexibility and reusability)

[pjungermann]

Allow users of this script to specify the software they like using an external file, e.g. a YAML file.

To consider:

• support current features
  • multiple package managers/installers
  • (optional) configuration per package (e.g., should override a previously installed version?)
  • shell support (Oh my Zsh) including plugins
• specification provided as optional argument
• provide opinionated specification within this repo which is used as default

Questions:

• keep using bash? E.g., ruby is preinstalled on MacOS, too, and might allow for easier coding and state management, etc. Ruby version conflicts could be an issue though. (e.g., different versions on different MacOS versions) Current version is very compatible and just requires one command.
• evolve this into a meta package manager which can be installed and itself installs supported package managers?

[pjungermann]

Use of Brewfile was used at PR #19

It could be more advanced.

Some inspiration:

• https://github.com/geerlingguy/mac-dev-playbook
• https://github.com/geerlingguy/dotfiles
• https://github.com/geerlingguy/ansible-collection-mac
• https://github.com/elliotweiser/ansible-osx-command-line-tools / https://galaxy.ansible.com/elliotweiser/osx-command-line-tools
• https://galaxy.ansible.com/lajarre/mac
• https://github.com/thoughtbot/laptop
• ...