[openexr] Update from 2 to 3.1.5, patch all consuming ports

[dg0yt]

• What does your PR fix?

  Updates openexr major version.
  Patches all consuming ports which don't natively support major version 3.
  Drops the cmake wrapper.

  Previous work: [openexr] Side-by-side installation of version 2 and 3 #26788 (side-by-side 2 and 3), [openexr3] Add new port #25238 (only adding openexr3), [openexr] Update to 3.1.5 #24249, [openexr] Update to 3.1.4 #20957 (direct updates of openexr).

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

  unchanged, no

• Does your PR follow the maintainer guide?

  yes

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

  yes

[dg0yt]

What to do with /guard:ehcont as used by directxtex, but absent in openexr?
a) Disabled it where used (directxtex (done), uvatlas (current error))
b) Add it upstream where necessary (at least openexr, imath)

Note that this problem is not a regression, but was already hidden behind optional directxtex[openexr]. It is just uncovered by specific test commits.

[github-actions]

You have modified or added at least one vcpkg.json where you should check the license field.

If you feel able to do so, please consider adding a "license" field to the following files:

• ports/ilmbase/vcpkg.json
• ports/pangolin/vcpkg.json

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[meshula]

Thank you for this patch! Looking forward to being able to use it :)

[JonLiu1993]

All features are tested successfully in the following triplet:

• x86-windows
• x64-windows
• x64-windows-static

[simogasp]

Great work! thanks for this.
If it can be merged I will close my draft #25238