BREAKING CHANGE:
The `ng add` command will now ask the user to confirm the package and version prior to installing and executing an uninstalled package.
This new behavior allows a user to abort the action if the version selected is not appropriate or if a typo occurred on the command line and an incorrect package would be installed.
A `--skip-confirmation` option has been added to skip the prompt and directly install and execute the package. This option is useful in CI and non-TTY scenarios such as automated scripts.
