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