SAMRAIConfig.cmake should call find_dependency(<thirdparty>) for all third-party packages that SAMRAI uses

[humhang]

My code uses SAMRAI which is compiled with umpire and RAJA, although my code itself does not use Umpire or RAJA.

In order for my code to compile, I have to explicitly add find_package(umpire) and find_package(RAJA) in my CMakeLists.txt, otherwise the targets of umpire and RAJA will not be imported, and I will have got a linking error. Although I should not need to do this, this should be done by SAMRAIConfig.cmake, the cmake config file of SAMRAI, via find_dependency(umpire) and find_dependency(RAJA), if SAMRAI is compiled with these libraries. This is somehow the standard practice. And downstream codes that use SAMRAI won't need to adjust their CMakeLists.txt depending on the configuration of SAMRAI.