scripts: twister: Unify Twister Statuses

Various different Statuses were joined into a single class,
TwisterStatus. This change anticipates further streamlining
of the Twister's approach to Status.

Code guarding Twister's Properties was shortened to a
value check only.

QEMUOutputStatus was left separate, as doubts were cast
whether it should remain a status. Leaving it separate makes
its removal easier.

Signed-off-by: Lukasz Mrugala <lukaszx.mrugala@intel.com>