feat(kv): add support for prefixed cursor search

[GeorgeMac]

Closes #16534

This introduces the new CursorOption known as WithCursorPrefix(prefix).

This option configures the returned cursor to only return keys with the provided prefix.

When using ForwardCursor with this new option. The provided seek bytes must be prefixed with the provided prefix bytes, otherwise the forward cursor implementation should return kv.ErrSeekMissingPrefix error and a nil cursor.

• CHANGELOG.md updated with a link to the PR (not the Issue)
• Well-formatted commit messages
• Rebased/mergeable
• Tests pass
• http/swagger.yml updated (if modified Go structs or API)
• Documentation updated or issue created (provide link to issue/pr)
• Signed CLA (if not already signed)

[stuartcarnie]

This is a great improvement 💯