* G-API/Samples: Added a simple "privacy masking camera" sample
The main idea is to host this code for an opencv.org blog post only
* G-API/Samples: Modified privacy masking camera code to look better for the post
* G-API/Samples: fix Windows (MSVC) support in Privacy Masking Camera
* G-API/Samples: Addressed the majority of review comments in PMC
* G-API/Samples: Use TickMeter to measure time + more info in cmd options
* G-API/Samples: fix yet another Windows warning in PMC
* G-API/Samples: Fix wording in PMC cmd arg parameters
* Fix wording, again
* G-API/Samples: Fix PMC cmd-line arguments, again
