Issue/711/jk cov kmeans

[Kabelo-T]

Description

fixes #711

Main changes

• implement kmeans clustering to partition sky for jackknife covariance calculation

Checklist

Besides passing all CI checks and coverage is at 100%, make sure you also checked the following items
(check details in CONTRIBUTING).

For developers

• Notebooks: notebooks related to this PR have been updated and all notebooks can run correctly.
• Build the documentation: All documentation builds correctly.

For reviewers

• Notebooks: notebooks related to this PR have been updated and all notebooks can run correctly.
• Build the documentation: All documentation builds correctly.

For developers (part 2)

After the PR has been approved by two reviewers:

• Update the code version in clmm/__ini__.py.
• Keep only relevant points in the squash and merge commit message.
• If any dependencies have been altered, update environment.yml, pyproject.toml, INSTALL.md, and README.md. A maintainer should also be notified to change the requirements on conda-forge.
• Update clmm/theory/_ccl_supported_versions.py and clmm/theory/ccl.py if pyccl's version constraints have been altered.

[coveralls]

coverage: 90.432% (-9.6%) from 100.0% — issue/711/jk_cov_kmeans into main