[tools/shoestring]: Output node certificate as x509 v3

[ccHarvestasya]

Problem

• CA certificates are output as x509 v3, but node certificates are output as x509 v1.

Solution.

• Output node certificate as x509 v3.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.72%. Comparing base (25b6fee) to head (6444e7d).
⚠️ Report is 1 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff            @@
##              dev    #1422    +/-   ##
========================================
  Coverage   96.71%   96.72%            
========================================
  Files         259      257     -2     
  Lines       17821    17965   +144     
  Branches      215      215            
========================================
+ Hits        17236    17377   +141     
- Misses        579      582     +3     
  Partials        6        6            

Flag	Coverage Δ
explorer-rest	?
lightapi-python	98.63% <ø> (-0.04%)	⬇️

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

Files with missing lines	Coverage Δ
...oestring/shoestring/internal/CertificateFactory.py	100.00% <ø> (ø)

... and 5 files with indirect coverage changes

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