Add option to skip scanner as a one-off

[AaronFeledy]

Maybe you know your app isn't going to succeed on the first build and you just want to get the containers up so you can start working on additional setup tasks, or you are debugging something and don't want to wait between lando rebuilds.

You can bail out of the scanner with CTRL+C, but many don't realize that this is possible or safe to do.

It would be nice to have an option like --skip-scanner that can be added to lando start or lando rebuild to bypass the scanner after the current build.