Serialization && deserialization for compile arguments

* Initial stub

* Add test on serialization of a custom type

* Namespaces rework

* Fix isSupported in test struct

* Fix clang lookup issue

* Initial implementation

* Drop the isSupported flag

* Initial implementation

* Removed internal header inclusion

* Switched to public API

* Implemented serialization

* Adding desirialize: WIP

* Fixed merge errors

* Implemented

* Final polishing

* Addressed review comments and added debug throw

* Added FluidROI test

* Polishing

* Polishing

* Polishing

* Polishing

* Polishing

* Updated CMakeLists.txt

* Fixed comments

* Addressed review comments

* Removed decay from deserialize_arg

* Addressed review comments

* Removed extra inclusion

* Fixed Win64 warning

* Update gcommon.hpp

* Update serialization.cpp

* Update gcommon.hpp

* gapi: drop GAPI_EXPORTS_W_SIMPLE from GCompileArg
Co-authored-by: NSmirnov Alexey <alexey.smirnov@intel.com>
Co-authored-by: NAsyaPronina <155jj@mail.ru>

Installation tutorials rework

* Doc: general installation, config reference, linux installation

* Doc: addressed review comments

* Minor fixes

[G-API] Numpy array with int64 failed in cv.gin

* Fix bug with numpy array precision in G-API python

* Fix comments to review

* update new RANSAC

* fix warning

* change gamma values table

* resolve conflict

* resolve conflict

* GammaValues as singleton

- keep logger available until the program termination

backported commit: 7fe87d9a

backported commit: 5fd3d36f

[GAPI] RMat integration into the framework

* RMat integration

* Added initialization of input mat in GArray initialization tests

* Fixed klocwork warnings in RMat tests, changed argument order in EXPECT_EQ

- define OPENCV_DISABLE_EIGEN_TENSOR_SUPPORT

* Modified for Intel Realsense webcam

* Fix whitespace

* Update page title

* Uppercase