cmake script to auto download and install the openjpeg dependency

[grdanny]

Description

sub task of : #4387
for sep 2025 dev days.

Adding a autobuild cmake file for openjpeg.

Matching the latest version like in the yet unmerged:
#4910

Tests

I built it locally - I can see it's downloading the files from github and building them.
I can run the tests.

Checklist:

• I have read the contribution guidelines.
• I have updated the documentation, if applicable. (Check if there is no
  need to update the documentation, for example if this is a bug fix that
  doesn't change the API.)
• I have ensured that the change is tested somewhere in the testsuite
  (adding new test cases if necessary).
• If I added or modified a C++ API call, I have also amended the
  corresponding Python bindings (and if altering ImageBufAlgo functions, also
  exposed the new functionality as oiiotool options).
• My code follows the prevailing code style of this project. If I haven't
  already run clang-format before submitting, I definitely will look at the CI
  test that runs clang-format and fix anything that it highlights as being
  nonconforming.

[lgritz]

Was there a reason you forced OFF here?

[lgritz]

In fact, this may be why the Windows test is failing.

[grdanny]

I was "learning" a bit from the build_PNG.cmake (and a few others that had it off).
let me try to set it from the LOCAL_BUILD_SHARED_LIBS_DEFAULT

[lgritz]

I think this is correct, but in ci.yml, in the "all local builds" job, you'll want to remove the setting of env variable OPENJPEG_VERSION=v2.5.4 because that will trigger the external script build_OpenJPEG.bash before the build. You don't want that, in this case you want to be sure you're forcing the autobuild one.