Added workflow for Github Actions to build and test OpenCV on Linux
* Added workflow for Github Actions to build and test OpenCV
* Merged a build and tests in one job, changed naming
* Renamed job names, split workflows by branch, removed and added some cmake flags, save unit tests results as a html file
* Split tests by steps, removed workflows for 4.x and 5.x branches
CI for TIM-VX backend
* github actions for TIM-VX backend https://github.com/opencv/opencv/pull/21036
* add reference to yuentau/ocv_ubuntu:20.04; remove extra quotes; enable BUILD_TESTS
* rename to timvx_backend_tests.yml
* add image source prefix
* remove if condition for x86_64 simulator
changed OpenCV license from BSD to Apache 2 license
* as discussed and announced earlier, changed OpenCV license from BSD to Apache 2. Many files still contain old-style copyrights though
* changed wording a bit; preserve the original OpenCV BSD license