Add images submenu functionality and notification displays

[unixorn]

Description

• Use Apple's Notification Manager (via osascript) to display notifications about some of our long-running tasks
  • Add displayAlert() for failure notifications so it doesn't disappear
  • Add displayNotification() that uses the macOS Notification Manager
  • Add notifications to image pull and remove operations
  • Add notifications to VM start/stop
• Add functionality to the image submenus
  • We now can pull or remove images from the lima menu
• Updated dependency checks
  • Add check for lima in $PATH
  • Add check for osascript in $PATH
• Makefile improvements
  • make i now runs shellcheck first

Type of changes

Checklist

• All new and existing tests pass.
• Any scripts added use #!/usr/bin/env interpreter instead of potentially platform-specific direct paths (#!/bin/sh and #!/bin/bash are allowed exceptions)
• Scripts are marked executable
• Scripts do not have a language file extension unless they are meant to be sourced and not run standalone. No one should have to know if a script was written in bash, python, ruby or whatever. Not including file extensions makes it easier to rewrite the script in another language later without having to change every reference to the previous version.
• I have confirmed that the link(s) in my PR are valid.

License Acceptance

• This repository is Apache version 2.0 licensed (some scripts may have alternate licensing inline in their code) and by making this PR, I am contributing my changes to the repository under the terms of the Apache 2 license.