arrow

ARROW-5575: [C++] Split Targets.cmake for each module

If we put all targets (arrow_shared, arrow_cuda_shared, parquet_shared
and so on) to one ArrowTargets.cmake, all targets are defined by
find_package(Arrow). It's not expected. arrow_shared should be defined
by find_package(Arrow), arrow_cuda_shared should be defined by
find_package(ArrowCUDA).

add_arrow_lib() changes:

  * Add CMAKE_PACKAGE_NAME option. If it's specified, CMake related
    files (ArrowConfig.cmake, ArrowConfigVersion.cmake,
    ArrowTargets.cmake and ArrowTargets-${BUILD_TYPE}.cmake) are also
    installed. You don't need to call
    arrow_install_cmake_find_module() explicitly. But you need to
    create ArrowConfig.cmake.in manually as usual.

  * Add PKG_CONFIG_NAME option. If it's specified, pkg-config related
    file (arrow.pc.in) is also installed. You don't need to call
    arrow_add_pkg_config() explicitly. But you need to create
    arrow.pc.in manually as usual.

Linux package changes:

  * Install newly created CMake related files.

  * CentOS: Extract Arrow Flight Python as arrow-python-flight from
    arrow-flight.

Closes #5798 from kou/cpp-split-targets and squashes the following commits:

4f8b30a01 <Sutou Kouhei> Accept "-" in arrow-config.cmake
5bd1a52b8 <Sutou Kouhei> ARROW-5575:  Split Targets.cmake for each module

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>