Add support for migrations within compute_ctl

[save-buffer]

Problem

It's easy bungle stuff with regards to permissions or other stuff. Fixing it is hard because we don't have a way to run a query on everyone's computes exactly once. Any migrations we currently do makes it so that we have to maek sure everything is ok to be run many times.

Summary of changes

Executes migrations on startup and persists the migrations inside of a table with a single row.

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]

2268 tests run: 2184 passed, 0 failed, 84 skipped (full report)

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Flaky tests (3)

Postgres 15

• test_secondary_mode_eviction: debug
• test_tenant_delete_races_timeline_creation: debug

Postgres 14

• test_logical_replication: release

Code coverage (full report)

• functions: 54.5% (10592 of 19429 functions)
• lines: 81.5% (60576 of 74351 lines)

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_{The comment gets automatically updated with the latest test results
d2e0d23 at 2024-01-18T22:13:04.545Z :recycle:}

[vadim2404]

@kelvich , you wanted to review this PR

[kelvich]

Looks good generally. I'd change migration tracking to be a bit more robust

[kelvich]

I think that is in a good state right now.

wonder if there is an easy way to feature-flag this and gradually roll it out. or at least region by region.

[kelvich]

cc @ololobus to be aware = )

[kelvich]

also tests are broken

[ololobus]

wonder if there is an easy way to feature-flag this and gradually roll it out. or at least region by region.

See for compute feature flags

• https://github.com/neondatabase/cloud/pull/9171
• [compute_ctl] Introduce feature flags in the compute spec #6016

I'm going to get use of them in #6008

[save-buffer]

Added support for these feature flags in https://github.com/neondatabase/cloud/pull/9450, will merge this PR once that one finishes