enable throttling of max number of pages that can be prerendered at once

[thescientist13]

Type of Change

• New Feature Request
• Documentation / Website
• Improvement / Suggestion
• Bug
• Other (please clarify below)

Summary

As noted in #699 , one thing we'e not doing is capping the max number of (in this case) browser tabs that are being opened at once by puppeteer. For a small site, opening 20 - 30 pages / tabs may not be an issue, but should Greenwood really open 100 browser tabs though if the site has 100 pages? i feel like at a decent amount of scale, this could break down pretty quickly. 🤔

Details

The thought process being that we can limit the number of max pages being being pre-rendered at once, be it puppeteer, or some other renderer (#709 ) can manage the firehose at their discretion, with maybe a default being detected based on system resources, or just a fixed number?

This should also be exposed through greenwood.config.js.