G-API: Refine Semantic Segmentation Demo #23766
### Overview
* Supported demo working with camera id (e.g `--input=0`)
* Supported 3d output segmentation models (e.g `deeplabv3`)
* Supported `desync` execution
* Supported higher camera resolution
* Changed the color map to pascal voc (https://cloud.githubusercontent.com/assets/4503207/17803328/1006ca80-65f6-11e6-9ff6-36b7ef5b9ac6.png)
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [ ] I agree to contribute to the project under Apache 2 License.
- [ ] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
[G-API] Support postprocessing for not argmaxed outputs
* Support postprocessing for not argmaxed outputs
* Fix typo
* Add assert
* Remove static cast
* CamelCast to snake_case
* Fix windows warning
* Add static_cast to uint8_t
* Add const to variables
G-API: IE. Adding support for INT32 type.
* Added support for int32
* Added sample for semantic-segmentation-adas-0001
* Alignment
* Alignment 2
* Rstrt build
* Removed test for sem seg
Anatoliy Talamanov
Maxim Pashchenkov
