feat: make optimization and splitChunks configurable

[pi0]

As a continuation to previous works on splitPages, this PR makes both optimization (webpack 4 option) and splitChunks fully customizable.

We can disable all splitting features using this option in nuxt.config.js:

build: {
    optimization: {
      splitChunks: {
        chunks: 'async',
      }
    },
    splitChunks: {
      pages: false,
      vendor: false,
      commons: false,
      runtime: false,
      layouts: false
    },
}

Other improvements with this PR

• Splitting for layout chunks disabled by default for performance
• shouldPrefetch is falsy by default to improve TTL
• resourcHints are disabled for dev mode

SPA Improvements

• Support render.shouldPrefetch and render.shouldPreload
• Disabled loadingIndicator to improve TTL
• Runtime chunk is inlined only for production

[codecov-io]

Codecov Report

Merging #3060 into dev will not change coverage.
The diff coverage is n/a.

@@         Coverage Diff          @@
##            dev   #3060   +/-   ##
====================================
  Coverage   100%    100%           
====================================
  Files         4       4           
  Lines        19      19           
  Branches      2       2           
====================================
  Hits         19      19

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[pi0]

Useful when locally debugging without the need to download puppeteer:

export PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=1

yarn install

# For macOS
export PUPPETEER_EXECUTABLE_PATH="/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"

We may also use this to speed up CI's setup stage by pre-downloading chrome...

[clarkdo]

NOTE: puppeteer/puppeteer#3071

[pi0]

Thanks @Clark 😁👌

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.