feat: failOnWarnings option

[rishabh3112]

What kind of change does this PR introduce?
feature

Did you add tests for your changes?
Yes

If relevant, did you update the documentation?
Done

Summary
adds --fail-on-warnings option
closes #3315

Does this PR introduce a breaking change?
No

Other information
#3315

[codecov]

Codecov Report

Merging #3317 (aaa1d84) into master (28b4403) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3317   +/-   ##
=======================================
  Coverage   92.09%   92.09%           
=======================================
  Files          23       23           
  Lines        1733     1733           
  Branches      519      519           
=======================================
  Hits         1596     1596           
  Misses        137      137           

Impacted Files	Coverage Δ
packages/webpack-cli/src/webpack-cli.ts	93.96% <100.00%> (ø)

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[webpack-bot]

@rishabh3112 Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@vankop Please review the new changes.