feat(sklplots): add confusion matrix normalized option

[shcheklein]

Adds an option to normalize confusion matrix like this:

live.log_sklearn_plot(
        "confusion_matrix",
        [0, 0, 1, 1],
        [0, 1, 1, 0],
        name="confusion_matrix_normalized",
        normalized=True,
    )

Quite handy to see a better heat map in case of classes being highly misbalanced.

---

• ❗ I have followed the Contributing to DVCLive
  guide.

• 📖 If this PR requires documentation updates, I have created a separate PR (or issue, at least) in
  dvc.org and linked it here.

Thank you for the contribution - we'll try to review it as soon as possible. 🙏

[shcheklein]

@daavoo @dberenbaum is it good to go? (I can create a doc PR then)

[shcheklein]

Docs PR is here treeverse/dvc.org#4486