[OpenCV] update to v4.5 and to v3.4.12

[cenit]

Update OpenCV to v4.5 (and v3.4.12)

Depends on: #15089
Fixes: #15479
Fixes: #15146
Fixes: #15108
Fixes: #15055
Fixes: #14368
Closes: #14118 (superseded, abandoned?)
Fixes: #13565
Fixes: #13098
Fixes: #13077
Fixes: #12740
Fixes: #12620
Fixes: #12587
Fixes: #11875

[JackBoosY]

Please consider support to CUDA 11, see the discussion.

[cenit]

OpenCV 4.5 supports CUDA 11 :)

[JackBoosY]

@cenit If you need any help. please ping me.

[cenit]

This PR (and anything related to OpenCV) really depends on #15089 being merged first, because it re-enables CI tests on this port. Otherwise the risk is of breaking the port even more.
I won't work on this PR before that one is merged

[elevir]

@cenit thanks for your work! I've tried to use your branch with opencv, but I've met a bug on windows. So, the bug is: share files are installing in folder share/opencv/${arch}/${vc}/lib, where OpenCVModules.cmake has incorrect relative path to libs (share/opencv/x64/lib). I think, config files should be moved in share/opencv instead of share/opencv/${arch}/${vc}. I've tried to figure out where the bug is, but at this time I couldn't do it. For now, I've manually moved this files into share/opencv and fixed OpenCV_INSTALL_PATH.

[cenit]

this branch is incomplete. I am waiting for some important fixes to be merged with master before pushing work here

[cenit]

@JackBoosY all configs should have been tested by CI and should pass.
Please let me know if you see anything strange/not working. Otherwise for me it's ready for merge

[cenit]

by the way @BillyONeal one thing might be improved about ci/regressions/baseline: if a regression is baselined in a "basic port", like qt5-tools:x64-windows-static-md, then with just a single line you are turning off many many ports from CI due to a very light "cascade" failure in all dependent ports (which in turn will get green mark in future even with a completely broken PR).

I don't know if I am clear enough, in case we can just discuss it in a different place because this PR is for sure not the right place.

[JackBoosY]

Need test features.

[cenit]

Need test features.

maybe not :)
If you check, CI is already testing all reasonable working features, thanks to vcpkg-ci-opencv which I put exactly for that.
In this way, I hope to protect also other ports from breaking features of OpenCV :)

(of course any additional test is extremely welcomed, but I just wanted to highlight you the vcpkg-ci-opencv so that you do not duplicate work)

[JackBoosY]

LGTM.

[JackBoosY]

Already merged from master.

[JackBoosY]

Thanks for @cenit 's hard work!
Thanks!