Feature/tensor prod

[agnesLeroy]

Resolves: zama-ai/concrete-core-internal#105

Description

Implement the GLWE tensor product in the core backend

Checklist

(Use '[x]' to check the checkboxes, or submit the PR and then click the checkboxes)

• [x] Tests for the changes have been added (for bug fixes / features)
• [x] Docs have been added / updated (for bug fixes / features)
• [x] The PR description links to the related issue (to link an issue, use '#XXX'.)
• [ ] The tests on AWS have been launched and are successful (apply the aws_test to the PR to launch the tests on AWS)
• [ ] The draft release description has been updated
• [x] Check for breaking changes and add them to commit message following the conventional commit specification