Remove CMAKE_CURRENT_BINARY_DIR path in rmm's target_include_directories

[trxcllnt]

This PR removes the CMAKE_CURRENT_BINARY_DIR path in rmm's target_include_directories.

Best I can tell, the build generates a version_config.hpp file and places it there for installation later. It doesn't seem to be included by any actual RMM library headers.

This breaks ccache in a few different ways:

• Building against different RMM build dirs:
  1. Build cuDF against RMM at rmm/build-dir-1 (note -I rmm/build-dir-1/include in cuDF compile commands).
  2. Rebuild cuDF against RMM at rmm/build-dir-2 (note -I rmm/build-dir-2/include in cuDF compile commands).
  3. ccache rebuilds all cuDF source files even though none of the RMM headers actually changed.
• Build RMM as a dependency of cuDF retrieved via CPM (with CPM_SOURCE_CACHE):
  1. Project A calls CPMFindPackage(cudf ...), cuDF and RMM are downloaded and placed in CPM_SOURCE_CACHE.
  2. Project B calls CPMFindPackage(cudf ...), which uses cuDF and RMM source cached in CPM_SOURCE_CACHE.
  3. The ccache for cuDF source files cannot be shared between Project A and Project B, because the compile command for each cuDF object includes -I ProjectA/build/_deps/rmm-build/include and -I ProjectB/build/_deps/rmm-build/include, respectively.

[harrism]

As long as the generated version header is still installed in the include directory when installed, I'm cool with this.

[trxcllnt]

@harrism yes, looks like it does:

[kkraus14]

@gpucibot merge