Custom client for hot reloading

[agubler]

Type: feature

The following has been addressed in the PR:

• There is a related issue
• All code has been formatted with prettier as per the readme code style guidelines
• Unit or Functional tests are included in the PR

Description:

The client from webpack-hot-client requires using the HotModuleReplacementPlugin as it deals with more complex scenarios than we support in dojo, such as reloading a single module. For dojo we only support an automatic reload of the page.

The HotModuleReplacementPlugin also modifies the bundle to support this which is not needed in the dojo build.

Adding a custom client that only deals with processing messages and either reloading the page or displaying the error overlay (still using the overlay from webpack-hot-client for the moment) and removes the requirement to use the HotModuleReplacementPlugin meaning that the bundles are not affected and are the same regardless of whether built with watch/serve or a standard build.

[codecov]

Codecov Report

Merging #111 into master will increase coverage by 0.05%.
The diff coverage is 82.95%.

@@            Coverage Diff             @@
##           master     #111      +/-   ##
==========================================
+ Coverage   84.01%   84.06%   +0.05%     
==========================================
  Files          37       38       +1     
  Lines        1389     1475      +86     
  Branches      372      385      +13     
==========================================
+ Hits         1167     1240      +73     
- Misses        222      235      +13

Impacted Files	Coverage Δ
src/bootstrap-plugin/async.js	0% <0%> (ø)	⬆️
src/bootstrap-plugin/sync.js	0% <0%> (ø)	⬆️
src/webpack-hot-client/client.js	84.88% <84.88%> (ø)

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