Add eviction_state to control file

[petuhovskiy]

This is a preparation for #8022, to make the PR both backwards and foward compatible.

This commit adds eviction_state field to control file. Adds support for reading it, but writes control file in old format where possible, to keep the disk format forward compatible.

Note: in patch_control_file, new field gets serialized to json like this:

• "eviction_state": "Present"
• "eviction_state": {"Offloaded": "0/8F"}

[github-actions[bot]]

3228 tests run: 3111 passed, 0 failed, 117 skipped (full report)

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Flaky tests (1)

#### Postgres 14 - `test_compute_pageserver_connection_stress`: [release](https://neon-github-public-dev.s3.amazonaws.com/reports/pr-8125/9604902842/index.html#suites/17ce3111e92c0f109f76121e2725061b/9156f0d3fda36267/retries)

Code coverage* (full report)

• functions: 32.3% (6850 of 21180 functions)
• lines: 49.8% (53374 of 107163 lines)

* collected from Rust tests only

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_{The comment gets automatically updated with the latest test results
735481e12b7f1493cbb1bb08e1987cfc6796a660 at 2024-06-20T23:30:25.988Z :recycle:}