Adds `ddev delete images --all flag`, fixes #2968 (#3615)
Adds `ddev delete images --all flag`, fixes #2968 (#3615)


drud/ddev,drud/ddev,rfay/ddev,drud/ddev,drud/ddev,rfay/ddev,rfay/ddev,rfay/ddev,drud/ddev,rfay/ddev