feat(pageserver): continue from last incomplete image layer creation

[skyzh]

Problem

close #10651

Summary of changes

• Image layer creation starts from the next partition of the last processed partition if the previous attempt was not complete.
• Add tests.

[github-actions]

7425 tests run: 7073 passed, 0 failed, 352 skipped (full report)

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Flaky tests (3)

Postgres 17

• test_lr_with_slow_safekeeper: release-arm64-without-lfc
• test_timeline_archive[4]: release-arm64-with-lfc
• test_s3_wal_replay: release-arm64-with-lfc

Code coverage* (full report)

• functions: 33.2% (8565 of 25792 functions)
• lines: 49.0% (71891 of 146780 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
1510bd1 at 2025-02-04T22:09:40.520Z :recycle:}