Use DoesCPUSupportFeature() in other projects

Moved feature defines into header. They should be in the header as part of the interface definition for SystemInformation::DoesCPUSupportFeature().

Added one particular feature FPU_FEATURE for completeness.

I want to make use of SystemInformation::DoesCPUSupportFeature() to extend CMake's cmCMakeHostSystemInformationCommand.cxx functionality and the change seems non-invasive (should not break any other project/code using kwsys).

Topic-rename: SystemInformation-cpu-feature-ids