Add mail.preview config to allow simpler conditional enabling, open door to other enhancments.

[spatie]

Add mail.preview config to allow simpler conditional enabling, open door to other enhancments.

[themsaid]

Hello :)

Yes please go ahead and open a PR, it sounds cool to me.

[coderabbi]

Awesome, thanks!

One odd bit of adding this and maintaining BC (obviously need to do that here), is that it would be possible to have mail.preview == false and mail.driver == preview in which case just looking at mail.preview would lead you to believe that they were turned off, but, of course, they would be turned on.

I don't think there's any way to escape that, and I think it's still worth it, but just wanted to note that after I sugested this, I realized it would be introducing a potentially confusing bit, albeit minor.

[themsaid]

I think it's fine if it works if either of the conditions is met.

[coderabbi]

#29