to reduce overhead of gradle builds

- eliminate CMake 3.5+ warnings
- removed usage of dropped "OPENCV_CAMERA_MODULES" variable
- partial support for Android NDK 11+

This retains the desirable quality of not including paths to CUDA libraries
from the build system into the config files, and has two major advantages:

* It removes the need to use link_directories, which doesn't guarantee that
  the libraries from the supplied directory will be used (there may be
  libraries with the same names earlier in the search path).

* It removes the need to put -L entries into OPENCV_LINKER_LIBS. This variable
  is used with target_link_libraries, where such entries are treated as linker
  flags, so doing this is unportable. I remove the support for -L entries
  from OpenCVGenPkgconfig.cmake, as well, to discourage adding them in the
  future.

(cherry picked from commit b10d4b05)

EMBED_CUDA and FORCE_EMBED_OPENCV flags added to cmake macro add_android_project;
INSTALL_CUDA_LIBRARIES option added to OpenCV.mk
opencv_dynamicuda library installation with enabled OPENCV_INSTALL_MODULES flag fixed;
CUDA initialization apportunity added to OpenCVLoader.initDebug();
Tutorial-4-CUDA sample reimplemented with static OpenCV and CUDA initialization.
(cherry picked from commit 6ae4a9b0)

save previous values of LOCAL_* variables and restore them at the end(cherry picked from commit 286fe261)

fix path to CUDA libraries (use targets/armv7-linux-androideabi/lib)(cherry picked from commit a098fb18)

EMBED_CUDA and FORCE_EMBED_OPENCV flags added to cmake macro add_android_project;
INSTALL_CUDA_LIBRARIES option added to OpenCV.mk
opencv_dynamicuda library installation with enabled OPENCV_INSTALL_MODULES flag fixed;
CUDA initialization apportunity added to OpenCVLoader.initDebug();
Tutorial-4-CUDA sample reimplemented with static OpenCV and CUDA initialization.

Native camera libs for MIPS installation fixed.

 [~] Automatically tracked dependencies between modules
 [+] Support for optional module dependencies
 [+] Options to choose modules to build
 [~] Removed hardcoded modules lists from OpenCVConfig.cmake, opencv.pc and OpenCV.mk
 [+] Added COMPONENTS support for FIND_PACKAGE(OpenCV)
 [~] haartraining and traincascade are moved outside of modules folder since they aren't the modules

Started top-level CMakeLists.txt file reorganization: cmake scripts are moved to separate folder; refactored BUILD_*, INSTALL_*, ENABLE_*, USE_*, WITH_* options.

Turned off android camera and java wrappers for low Android API levels (android-8 is required for these components)