feat(xpress): add direct io

[CharlieFModo]

Closes # (if applicable).

Changes proposed in this Pull Request

• Adds xpress direct solver IO
• To ensure xpress direct IO is faster than lp-polars this PR removes pandas from the hot-path of matrix operations required to get problem coefficients to write to xpress
  • This seems to have large performance gains throughout the package beyond what I have tested for this PR
  • I would like some guidance on whether these changes are ok in the broader context of the package. I've only tested them on the problems that I am interested in solving and found this gives a c. 10x improvement from the lp-polars IO

Checklist

• Code changes are sufficiently documented; i.e. new functions contain docstrings and further explanations may be given in doc.
• Unit tests for new features were added (if applicable).
• A note for the release notes doc/release_notes.rst of the upcoming release is included.
• I consent to the release of this PR's code under the MIT license.