Defaults for running safeClassNames

[cossssmin]

This PR changes the way the safeClassNames Transformer runs by default.

It now:

• doesn't run when env is local (developing locally, like with maizzle serve)
  • exception: will run locally if explicitly set to true
• doesn't run if explicitly disabled (safeClassNames: false)

This makes it a little easier to debug when developing locally and inspecting the code - by default now you get to see the Tailwind classes exactly as you wrote them.