Refactoring suggestion of the application workflow

[gponcon]

It might be worth having a refactoring of the script so that it works in this way:

1. Existing installation detection (shell, DE, configurations...)
2. Ask the user what they want (ask them all the questions)
3. Check that responses is consistent and save the installation configuration somewhere (as archinstall does, for example).
4. Install (do not touch the system before), recording the progress for each stage completed successfully, so that if the script fails, you can start again from the right step.