backport commit 659ffadd

* cmake: avoid deprecated LINK_PRIVATE/LINK_PUBLIC

see CMP0023 (CMake 2.8.12+)

* cmake: fix 3rdparty list

- don't include OpenCV modules

except header file with conversion routines (will be removed in OpenCV 4.0)

- allow installing samples sources on all platforms
  even if BUILD_EXAMPLES is disabled,  fixed minor
  issues in sources installation process
- use 'example_<group>_<name>' scheme for target and binary file naming
- use single function for sample executable creation

some tutorials depends on contrib modules

(cherry picked from commit 341e7b3b)

(cherry picked from commit bba8c0be)

(cherry picked from commit ff002203)

Get rid of cvconfig.h in Latent SVM samples. Use common OpenCV parallel framework instead of direct TBB calls.

fixed dependency of stitching module on xfeatures2d module as optional
fixed the initModule_xfeatures2d function that was called in module stitching since it is in another namespace than the standard cv one.

removed contrib, legacy and softcsscade modules; removed latentsvm and datamatrix detector from objdetect. removed haartraining and sft apps.
some of the stuff will be moved to opencv_contrib module.
in order to make this PR pass buildbot, please, comment off opencv_legacy, opencv_contrib and opencv_softcascade test runs.

Env setup for testing package implemented using /etc/profile.d;
Variable with path for all native samples added;
Path for test binaries and test data updated.
(cherry picked from commit 39201e68)

(cherry picked from commit f332cba1)

Env setup for testing package implemented using /etc/profile.d;
Variable with path for all native samples added;
Path for test binaries and test data updated.

(cherry picked from commit b75cbfde)

Conflicts:

	cmake/OpenCVModule.cmake