Change script order, add fusion-cli peer dependency

[rtsao]

• Moves execution of critical (preloaded) async chunks before "sync" chunks
• Enforces usage of fusion-cli version 1.2.2 or newer (i.e. versions of fusion-cli using webpack 4)

This will eventually allow for the removal of our custom chunk preloading code (needed in webpack 3 and older)

[codecov]

Codecov Report

Merging #257 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #257   +/-   ##
=======================================
  Coverage   92.25%   92.25%           
=======================================
  Files          18       18           
  Lines         413      413           
  Branches       79       79           
=======================================
  Hits          381      381           
  Misses         17       17           
  Partials       15       15

Impacted Files	Coverage Δ
src/plugins/ssr.js	94.36% <100%> (ø)	⬆️

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[rtsao]

!merge