This commit introduces a POM.xml file to allow the build of OpenCV and Java bundles using Maven.

An additonal directory has been created  'platforms/maven' to contain the POM and scripts used during the build process. An additional Markdown file is included to give instructions on how to build with Maven.

CPack can't work with absolute paths.

opencv_ts is static internal library and in case of exporting
it requires all static dependencies (include HAL files)

Linker dependencies are transitive for non-private

- removed OpenCV_LIB_DIR* vars (they are broken and not required anymore)
- OpenCVConfig.cmake doesn't contain ANDROID/CUDA code if there is no such support
- removed OpenCV2_INCLUDE_DIRS_CONFIGCMAKE, merged into OpenCV_INCLUDE_DIRS_CONFIGCMAKE
- fix hard-coded relative paths for OpenCV_INSTALL_PATH
- removed OpenCV_TBB_ARCH
- switch OpenCVConfig.cmake into 2-level mode for Android SDK

Some CMake 3.x (2.8.12.2 is fine) provides broken build configurations
with following build error message:
    ld: fatal error: -soname: must take a non-empty argument

Linker command line sample contains this:
"-shared -Wl,-soname, -o"

combinations of translation, rotation, and uniform scaling equals four degrees of freedom

Correcting return type from videoDevice::findType to be int thus allowing detection of failed device init request

  * loosen the threshold only under aarch64
  * fix #6610