feat: Default and overridable solve and root computation methods.

[daniel-dodd]

Post #370, akin to kernel / likelihood quadrature computation, would be good to have on the top level default methods for these defined on the Prior that say what solver and root method we'd like to have, defaulting to Cholesky-based methods.

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[github-actions]

There has been no recent activity on this issue. To keep our issues log clean, we remove old and inactive issues.
Please update to the latest version of GPJax and check if that resolves the issue. Let us know if that works for you by leaving a comment.
This issue is now marked as stale and will be closed if no further activity occurs. If you believe that this is incorrect, please comment. Thank you!

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There has been no activity on this PR for some time. Therefore, we will be automatically closing the PR if no new activity occurs within the next seven days.
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