feat : Added support for proxy definitions

[k-rajat19]

This PR can close #1701 which was opened as a feature request by @shamasis .

• Feature
• Update docs
• Add tests

Not sure about which proxy server should be used for writing tests , should we need to create a proxy server using
http-proxy or something else need to be done ?

Any suggestions/changes in this PR which leads to closing the above issue are welcome.

[codecov]

Codecov Report

Merging #2923 (8bd3d8f) into develop (a5018ec) will decrease coverage by 0.20%.
The diff coverage is 78.94%.

@@             Coverage Diff             @@
##           develop    #2923      +/-   ##
===========================================
- Coverage    90.96%   90.76%   -0.21%     
===========================================
  Files           21       21              
  Lines         1151     1169      +18     
  Branches       349      356       +7     
===========================================
+ Hits          1047     1061      +14     
- Misses         104      108       +4     

Flag	Coverage Δ
cli	82.03% <73.68%> (-0.16%)	⬇️
integration	40.54% <15.78%> (-0.47%)	⬇️
library	58.85% <78.94%> (+0.29%)	⬆️
unit	74.08% <15.78%> (-0.99%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
bin/newman.js	89.79% <ø> (ø)
lib/run/options.js	93.19% <75.00%> (-2.23%)	⬇️
lib/run/index.js	93.84% <100.00%> (+0.09%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a5018ec...8bd3d8f. Read the comment docs.

[shamasis]

This looks great. I have one suggestion.

We should use this opportunity to see how we can load these from a general config concept. Now, that may become slightly out of scope for this PR, hence to keep this sane and forward compatible, let's put the config's definition to be an array within an object.

{
  "proxies": [...]
}

PS: Meeting the test coverage (and changelog.yaml) will also be super cool and avoid someone else from needing to deep dive the PR post merge.

[k-rajat19]

hi @shamasis , i have added new commits also tried to adding some test cases as well
can you please look into this