Documentation generation refactoring (#10621)

* Documentation build updates:

- disable documentation by default, do not add to ALL target
- combine Doxygen and Javadoc
- optimize Doxygen html

* javadoc: fix path in build directory

* cmake: fix "Documentation" status line

- fix imports override.
  Problem is observed with BoostDesc.

- add Ptr<> handling (constructor is protected from other packages).
  Observed in ximgproc:
      Ptr<StereoMatcher> createRightMatcher(Ptr<StereoMatcher> matcher_left)"
  where, "StereoMather" is from another package (calib3d)

intermediate commit (to simplify code review)

Adding capability to parse subsections of a byte array in Java bindings (#10489)

* Adding capability to parse subsections of a byte array in Java bindings. (Because Java lacks pointers. Therefore, reading images within a subsection of a byte array is impossible by Java's nature and limitations. Because of this, many IO functions in Java require additional parameters offset and length to define, which section of an array to be read.)

* Corrected according to the review. Previous interfaces were restored, instead internal interfaces were modified to provide subsampling of java byte arrays.

* Adding tests and test related files.

* Adding missing files for the test.

* Simplified the test

* Check was corrected according to discussion. An OutOfRangeException will be thrown instead of returning.

* java: update MatOfByte implementation checks / tests

Bitwise "and false" is always false.

OpenCV 3.4.0-rc

Support @deprecated tag in java wrappers (#9698)

Add Android Mat constructor with support for native buffer (#10050)

for non-ANDROID platforms

Previous commit, 6f39f9a6, tries to fix the color issue for emulator. But the condition for detecting emulator is incomplete, e.g. it stops working for emulators using Google Play, whose Build.BRAND=="google". https://stackoverflow.com/a/21505193 shows a more accurate condition for this.

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

* Introduced OSGi Blueprint XML file and Bean class too automatically load the native library.

* Introduced integration testing module to deploy to Karaf OSGi implementation.

* Clears library executable stack flag during build.

* Updated README document.

Synchronizing against non-final fields is advised against.

* Use the YV12 format in the Android emulator to avoid image issues

* Removed trailing spaces

* Added exception in else case

* Removed tab

3.2.0-rc