feat(pageserver): compute aux file size on initial logical size calculation

[skyzh]

Problem

close #7822
close #7443

Summary of changes

Aux file metrics is computed incrementally. If the size is not initialized, the metrics will never show up. This pull request adds the functionality to compute the aux file size on initial logical size calculation.

Checklist before requesting a review

• 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.

Checklist before merging

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

[github-actions]

3186 tests run: 3047 passed, 0 failed, 139 skipped (full report)

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Flaky tests (2)

Postgres 16

• test_vm_bit_clear_on_heap_lock: debug

Postgres 14

• test_subscriber_restart: release

Code coverage* (full report)

• functions: 31.5% (6570 of 20885 functions)
• lines: 48.4% (50828 of 105005 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
a2344b9 at 2024-06-04T16:53:06.999Z :recycle:}