Define FLOW3_SAPITYPE constant in bootstrap
IMO global constants are as bad as global variables. So I'm happy there are only 4 constants needed yet in FLOW3.
They're all defined in FLOW3-bootstrap - except FLOW3_SAPITYPE, that's defined in the constructor of F3\FLOW3\Utility\Environment if it hasn't been defined before.
Attached patch fixes this. But maybe \F3\FLOW3\Utility\Environment::getSAPIType() could be a static method too so we wouldn't need to instantiate it at all and could move the Constant-definition up to the other three defines()...