feat(JXL): CICP read and write support for JPEG XL

[brechtvl]

Description

The JPEG XL color encoding metadata only supports a subset of CICP. So for example srgb_p3d65_display and pq_rec2020_display are supported, but g26_xyzd65_display is not.

Custom primaries, custom white point and arbitrary gamma could be used to support more, but I didn't implement that.

Tests

Tests for read and write were added.

Checklist:

• [x] I have read the contribution guidelines.
• [x] 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.)
• [x] I have ensured that the change is tested somewhere in the testsuite (adding new test cases if necessary).
• [x] 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).
• [x] 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.

[brechtvl]

~~Draft because this depends on and includes the changes from #4964.~~