enforce Async suffix for async functions

[dsokal]

Checklist

• I've added an entry to CHANGELOG.md if necessary.
• I've tagged the changelog entry with [EAS BUILD API] if it's a part of a breaking change to EAS Build API (only possible when updating @expo/eas-build-job package).

Why

We use Async suffix for async functions. Unfortunately, we haven't had any eslint rule that would enforce that convention.

How

• I installed https://github.com/IPWright83/eslint-plugin-async-protect and enabled the async-protect/async-suffix rule for all files except tests and mocks (mostly because jest.fn() does not return an async function).
• I refactored all CLI command classes so they extend the EasCommand class. This let me avoid adding the eslint-disable-next-line statement in every command class. (cc @kgc00)

Test Plan

CI

[github-actions]

Size Change: -1.62 kB (0%)

Total Size: 27.1 MB

Filename	Size	Change
./packages/eas-cli/dist/eas-linux-x64.tar.gz	27.1 MB	-1.62 kB (0%)

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