set the default CMAKE_BUILD_TYPE to RelWithDebInfo to improve the reconstruction speed
@zhangyz find the reconstruction speed of ACTS in CEPCSW and standalone ACTS are different. After debugging, we found that the optimization mode is not enabled in CEPCSW.
In order to improve the speed and keep the debugging information in the current stage, we adopt the RelWithDebInfo
as the default value.
Edited by lintao@ihep.ac.cn