feat: delay loading error-callsites module

[astorm]

Closes: #2833

Delays loading of error-callsites to agent start to avoid unwanted prepareStackTrace side effects prior to the agent starting.

Checklist

• Implement code
• Add tests
• Update TypeScript typings
• Update documentation
• Add CHANGELOG.asciidoc entry

[apmmachine]

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• Start Time: 2022-09-07T21:31:17.656+0000

• Duration: 18 min 19 sec

Test stats 🧪

Test	Results
Failed	0
Passed	259126
Skipped	0
Total	259126

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[astorm]

@trentm still working up a test or two on this one but wanted to run the idea of wrapping error-callsites in a lazy load callback and then explicitly loading it in Agent.start. Was this what you had in mind or was there another approach you were considering?

[trentm]

Looks good.