clean up hypre dependency install

[sslattery]

The hypre dependency was not being correctly installed so downstream packages would have had to included hypre in their CMAKE_PREFIX_PATH even though it is an implementation detail in Cajita. This PR adds proper install for this.

[sslattery]

@junghans I can't quite figure out how to get the downstream package to use FindHYPRE.cmake when it finds Cabana in the prefix path. Here is my current error with ExaMPM:

> ./configure.sh
-- The CXX compiler identification is AppleClang 11.0.0.11000033
-- Check for working CXX compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++
-- Check for working CXX compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ - works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found MPI_CXX: /Users/uy7/install/openmpi-4.0.0/lib/libmpi.dylib (found version "3.1")
-- Found MPI: TRUE (found version "3.1")
-- Enabled Kokkos devices: SERIAL
-- Enabled Kokkos devices: SERIAL
-- Found MPI: TRUE (found version "3.1") found components: CXX
CMake Error at /opt/local/share/cmake-3.17/Modules/CMakeFindDependencyMacro.cmake:47 (find_package):
  By not providing "FindHYPRE.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "HYPRE", but
  CMake did not find one.

  Could not find a package configuration file provided by "HYPRE" with any of
  the following names:

    HYPREConfig.cmake
    hypre-config.cmake

  Add the installation prefix of "HYPRE" to CMAKE_PREFIX_PATH or set
  "HYPRE_DIR" to a directory containing one of the above files.  If "HYPRE"
  provides a separate development package or SDK, be sure it has been
  installed.
Call Stack (most recent call first):
  /Users/uy7/install/Cabana/debug/lib/cmake/Cabana/CabanaConfig.cmake:11 (find_dependency)
  CMakeLists.txt:12 (find_package)


-- Configuring incomplete, errors occurred!
See also "/Users/uy7/build/ExaMPM/debug/CMakeFiles/CMakeOutput.log".

[sslattery]

Travis isn't reporting back but the downstream testing for external packages is breaking in some builds:

~/build/ECP-copa/Cabana/example/tutorial/01_hello_world/build ~/build/ECP-copa/Cabana/example/tutorial/01_hello_world
2815-- The C compiler identification is GNU 7.5.0
2816-- The CXX compiler identification is GNU 7.5.0
2817-- Check for working C compiler: /usr/lib/ccache/gcc
2818-- Check for working C compiler: /usr/lib/ccache/gcc -- works
2819-- Detecting C compiler ABI info
2820-- Detecting C compiler ABI info - done
2821-- Detecting C compile features
2822-- Detecting C compile features - done
2823-- Check for working CXX compiler: /usr/lib/ccache/g++
2824-- Check for working CXX compiler: /usr/lib/ccache/g++ -- works
2825-- Detecting CXX compiler ABI info
2826-- Detecting CXX compiler ABI info - done
2827-- Detecting CXX compile features
2828-- Detecting CXX compile features - done
2829-- Enabled Kokkos devices: SERIAL
2830-- Found MPI_CXX: /usr/lib/x86_64-linux-gnu/openmpi/lib/libmpi_cxx.so (found version "3.1") 
2831-- Found MPI: TRUE (found version "3.1") found components:  CXX 
2832-- Configuring done
2833CMake Error at CMakeLists.txt:9 (add_executable):
2834  Target "HelloWorld" links to target "ArborX::ArborX" but the target was not
2835  found.  Perhaps a find_package() call is missing for an IMPORTED target, or
2836  an ALIAS target is missing?

I'm surprised ArborX isn't getting picked up

[sslattery]

ah it was related to #245! @junghans you beat me to it