[opencv4] update from 4.3.0 to 4.5.1

[ludchieng]

• What does your PR fix?

Update opencv 4.3.0 to 4.5.1
Gives access to new opencv contrib modules

• Which triplets are supported/not supported? Have you updated the CI baseline?

Tested on x64-windows

• Does your PR follow the maintainer guide?

Yes, we tried

[Draft] There are two remaining problems:

• We commented patches for opencv 4.3.0 in the portfile.cmake as we don't know how to update them for 4.5.1
• OpenCVModules.cmake is now installed in "installed/x64-windows/share/opencv/x64/vc16/lib" instead of "installed/x64-windows/share/opencv". As _IMPORT_PREFIX variable is based on this relative path, cmake fails to find the librairies files.

[ghost]

All CLA requirements met.

[JackBoosY]

cc @Neumann-A @cenit for review this PR.

[cenit]

nope, this pr is not valid. It does not even bother to disable automatic download of packages...

[fabiencastan]

The PR has been created in DRAFT and explicitely says that it is not ready. There are 2 issues:

• patches needs to be upgraded
• OpenCVModules.cmake needs to be fixed due to changes in opencv cmake files.

Could someone with an experience on this package help us or guide us to make the upgrade?

[fabiencastan]

An update to 4.5 has already been started in #15162.