[ADD] Implement XTrace trace estimator

[f-dangel]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 12672382119

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 31 of 33 (93.94%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 93.338%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
curvlinops/trace/epperly2024xtrace.py	30	32	93.75%

Totals
Change from base Build 12573122785:	0.01%
Covered Lines:	1415
Relevant Lines:	1516

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💛 - Coveralls

[runame]

I don't fully understand the algorithm (would have to look at the paper for that), but the implementation LGTM.