[WIP] feat(pageserver): dio-aligned buffer allocation

[yliang412]

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• I have performed a self-review of my code.
• If it is a core feature, I have added thorough tests.
• Do we need to implement analytics? if so did you add the relevant metrics to the dashboard?
• If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section.

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• Do not forget to reformat commit message to not include the above checklist

[github-actions]

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_{The comment gets automatically updated with the latest test results
53b3f9f at 2024-08-14T23:54:54.420Z :recycle:}

[yliang412]

Closed in favor of #8730.