Add Zsh Completion Script Generation and Unit Tests

[954alberto]

Summary: This PR introduces enhancements to the cargo-make tool by adding task completion script generation functionality per shell. Key updates include, in this case only Zsh was added:

Directory and File Management:

Automatically creates the ~/.zfunc directory if it does not exist.
Prompts users before overwriting the completion file if it already exists.
User Guidance:

Outputs clear instructions for enabling Zsh completions by modifying the ~/.zshrc file.
Testing Improvements:

Added unit tests for the completion generation function, including tests for user input handling and file creation.
Tests have been designed to clean up the test environment to avoid interference between test cases.

Ensures that the functionality can be tested without manually interacting with the terminal.