G-API: Introduced Security Barrier & Interactive Face Detection samples

* G-API-NG/Samples: Added samples & relevant changes

- Security barrier camera sample
- Age/Gender/Emotions recognition sample
- GIEBackend now loads CPU extension libraries
- A couple of API-level workarounds added to deal with cv::Mat/Blob conversions

* G-API-NG/Samples: removed HAVE_INF_ENGINE remnants

* Fix infinite loop when trying to change state of the busy camera

  - Add finite number of attempts in tryIoctl functions
    10 by default.

* Introduced new flag for ioctl call to handle EBUSY

* Fix android armv7 c++_static init crash

* core: move initialization of 'ios_base::Init' for Android

- do not require extensions library

Improving VSX performance of integral function

* Adding support for vector get function on VSX datatypes so the
integral function gains a bit of performance.

* Removing get as a datatype member function and implementing a new HAL
instruction v_extract_n to get the n-th element of a vector register.

* Adding SSE/NEON/AVX intrinsics.

* Implement new HAL instruction v_broadcast_element on VSX/AVX/NEON/SSE.

* core(simd): add tests for v_extract_n/v_broadcast_element

- updated docs
- commented out code to repair compilation
- added WASM and MSA default implementations

* core(simd): fix compilation

- x86: avoid _mm256_extract_epi64/32/16/8 with MSVS 2015
- x86: _mm_extract_epi64 is 64-bit only

* cleanup

core(test): extending tests with SIMD C++ emulation code (intrin_cpp.hpp)

* core(test): test SIMD CPP emulation code (intrin_cpp.hpp)

* core(simd): eliminate build warnings from intrin_cpp.hpp

- backport 15290
- add extra test case

Add retrieve encoded frame to VideoCapture

* Add capacity to retrieve the encoded frame from a VideoCapture object.

* Correct raw codec and pixle format output from ffmpeg capture.

* Remove warnings from build.

* Added VideoCaptureRaw subclass.

* Include abstract base class VideoCaptureBase and rename new subclass VideoContainer as suggested by mshabunin.

* Remove using.

* Change base class name for compatibility with jave bindings generator.

* Move grab and retrieve and add override specifier

* Add setRaw and readRaw to IVideoCapture interface
-setRaw to disable video decoding and enable bitstream filters from mp4 to h254 and h265.
-readRaw to return the raw undecoded/filtered bitstream.
Add createRawCapture to initiate a backend with setRaw enabled.
Remove inheritance and use an independant VideoContainer subclass with IVideoCapture member.

* Address unused parameter warings.
Remove VideoContainer from python bindings as it no longer returns a Mat.
Use opencv type uchar instead of unsigned char.
Add missing destructor to VideoContainer class.

* Address build warnings and include all params in documentation.

* Include deprecated bitstream filtering API.

* Update codec_id query to work with older ffmpeg api's.
Change api version defines to be consistent - most recent api version first.

* Fix typo.

* Update test to work with naming of new files in the extra repo

* Investigate test failure

* Check bytes read by ffmpeg

* Removed mp4 video container test

* Applied suggested changes.

* videoio: rework API for extraction of RAW video streams

- FFmpeg only

* address review comments

Introducing the sample of Face Beautification algorithm implemented via Graph-API

* Introducing the sample of Face Beautification algorithm implemented via Graph-API
- 'gapi/samples/face_beautification.cpp' added
- FIXME added in 'gcpukernel.hpp'

* INF_ENGINE fix
- preprocessing clauses added not to run the sample without Inference Engine

* INF_ENGINE fix 2
- warnings removed

* Fixes
- checking IE version cut as there is no dependency
- some alignments fixed
- the comment about preprocessing commands fixed

* ie::backend() issue fix (according to dmatveev)
- as the sample needs the cv::gapi::ie::backend() to be defined regardless of having IE or not, there is its throw-error definition in `giebackend.cpp` now (by dmatveev)
- for the same reason, #includes in `giebackend.hpp` are fixed
- HAVE_INF_ENGINE check is removed from the sample

* imgproc: fix bit-exact GaussianBlur() / sepFilter2D()

- avoid kernels with bad approximation
- GaussiabBlur - apply error-diffusion approximation for kernel (8-bit fraction)

* java(test): update features2d ref data

* test: update test_facedetect