Add implementation ZSH using the Trait file defining actions

[arnenator]

This issue contains different sub tasks that needs to be investigated before this issue can be considered closed:

• Research what ~/zshenv and /etc/zprofile does.
  • Document your findings
• Document it under Supported Environment Variable files
• Create the implementation of the trait file for ZSH
• Implement each function in zsh_handler.rs #17
• Implement a way to contain script code in the parse_environment_variables code #19
• Clean Variables and use of different types #20
• Create tests
• Add readme explanation of how it works and how to use the EVC