create-site: Add check for Valet and run secure

[brettsmason]

A nice to have feature for Valet users would be to check if Valet is available and run valet secure as an additional step if https was selected during the questions. Not sure how viable that is or not. Some helpful code may be in this repo.

[brettsmason]

@edjeavons Not sure if this is really needed now we all use Herd. What do you think? Could be changed to Herd, but its only a click to secure it in the GUI.