feat(context): return GIN Context from Value method

[ifaisalalam]

Closes #2824

[codecov]

Codecov Report

Merging #2825 (2f7c905) into master (b463b1c) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #2825      +/-   ##
==========================================
+ Coverage   98.71%   98.76%   +0.04%     
==========================================
  Files          41       41              
  Lines        2100     3065     +965     
==========================================
+ Hits         2073     3027     +954     
- Misses         15       26      +11     
  Partials       12       12              

Flag	Coverage Δ
go-1.13	98.76% <100.00%> (?)
go-1.14	98.59% <100.00%> (?)
go-1.15	98.59% <100.00%> (?)
go-1.16	98.59% <100.00%> (?)
go-1.17	98.49% <100.00%> (?)
macos-latest	98.76% <100.00%> (?)
nomsgpack	98.74% <100.00%> (?)
ubuntu-latest	98.76% <100.00%> (?)

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

Impacted Files	Coverage Δ
context.go	97.99% <100.00%> (+0.26%)	⬆️
render/json.go	83.14% <0.00%> (-2.15%)	⬇️
gin.go	99.09% <0.00%> (-0.09%)	⬇️
utils.go	96.80% <0.00%> (-0.02%)	⬇️
fs.go	100.00% <0.00%> (ø)
auth.go	100.00% <0.00%> (ø)
mode.go	100.00% <0.00%> (ø)
path.go	100.00% <0.00%> (ø)
tree.go	100.00% <0.00%> (ø)
debug.go	100.00% <0.00%> (ø)
... and 32 more

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[ifaisalalam]

Hi @appleboy @thinkerou @javierprovecho! Could you please help review this PR?

I have described the use case in the issue #2824.

Thanks!

[appleboy]

@thinkerou Please help to review.