fix: the --help option is working without webpack-dev-server

[alexander-akait]

What kind of change does this PR introduce?

bugfix

Did you add tests for your changes?

partial, hard to tests due yarn workspaces

If relevant, did you update the documentation?

No need

Summary

Allow to lazy installation and loading options for commands

Does this PR introduce a breaking change?

No

Other information

fixes #2266

[alexander-akait]

TODO fix: webpack serve --open without webpack-dev-server

[codecov]

Codecov Report

Merging #2267 (c031719) into master (952a188) will increase coverage by 0.22%.
The diff coverage is 77.04%.

@@            Coverage Diff             @@
##           master    #2267      +/-   ##
==========================================
+ Coverage   67.82%   68.04%   +0.22%     
==========================================
  Files          63       63              
  Lines        2415     2438      +23     
  Branches      544      548       +4     
==========================================
+ Hits         1638     1659      +21     
- Misses        777      779       +2     

Impacted Files	Coverage Δ
packages/webpack-cli/lib/webpack-cli.js	90.99% <68.42%> (-0.80%)	⬇️
packages/serve/src/index.ts	66.10% <85.71%> (+7.08%)	⬆️
packages/generators/src/index.ts	100.00% <100.00%> (ø)
packages/info/src/index.ts	100.00% <100.00%> (ø)
packages/init/src/index.ts	90.90% <100.00%> (ø)
packages/migrate/src/index.ts	88.88% <100.00%> (ø)
...kages/webpack-cli/lib/utils/prompt-installation.js	57.69% <100.00%> (-1.57%)	⬇️

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[alexander-akait]

Really hard to tests due we use execa, plus removing and installation again break other tests, I will thinks about it more deeply when we focus on coverage (i.e. 4.5 version), tested manually

[alexander-akait]

We already have this test in core-flags, so it is duplicate