fix(build): move cppunit_main in cmake/build folder

Description

Fix the build of unit test on external projects.

• cppunit_main.cpp has been moved from cmake/cppunit to cmake/build folder.
• FindOpenNI2.cmake has been removed
• fw*.cmake files has been removed, contents was added in cmake/build/macros.cmake file in order to be retrieved from outside.

Closes #687 (closed)

How to test it?

Create unit test using the sight_add_target( tutuTest TYPE TEST) macro from outside of sight.