Types of changes

This PR presents a vectorized implementation of LpL1 transport algorithms for domain adaptation, along with all the requisite modifications to ensure compatibility of the ot.da module with JAX.

Motivation and context / Related issue

Continuing the effort to enable Domain Adaptation functionality in JAX. See also previously introduced changes in PR #587 for details.

How has this been tested (if it applies)

The tests have been updated. Additionally, a dedicated test has been included to verify that the vectorized implementation produces the same results as the original code.

PR checklist

• I have read the CONTRIBUTING document.
• The documentation is up-to-date with the changes I made (check build artifacts).
• All tests passed, and additional code has been covered with new tests.
• I have added the PR and Issue fix to the RELEASES.md file.