feat(lint): implement noPrivateImports

[arendjr]

Summary

This implements the new rule noPrivateImports based on the previous noPackagePrivateImports (called useImportRestrictions in 1.x).

I've moved the rule to the correctness group, since it seems that repositories that would like to enforce such visibility rules would consider code that imports restricted symbols to be incorrect.

I've made the rule part of the recommended set as well. This was made possible by changing the default visibility to public, meaning that the rule should only report on symbols with explicit visibility restrictions. For symbols with explicit restrictions, it seems sensible that we show diagnostics by default.

Furthermore, by enabling the rule by default, it gives us an opportunity to see the impact of the rule's performance in the real world. If users complain about the rule's behaviour or its performance, we can still remove it from the recommended set before 2.0 is final.

Thanks to @siketyan for helping with the implementation.

Test Plan

Tests added.

[codspeed-hq]

CodSpeed Performance Report

Merging #5388 will not alter performance

_{Comparing arendjr:no-private-imports (a1cd8fa) with main (772dcf5)}

Summary

✅ 95 untouched benchmarks