feat: Update NestJS onboarding

[lforst]

Updates the NestJS onboarding docs and fixes broken links.

[nicohrubec]

lgtm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.03%. Comparing base (6560123) to head (4b2c02b).
Report is 7 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #73577      +/-   ##
==========================================
- Coverage   78.03%   78.03%   -0.01%     
==========================================
  Files        6638     6638              
  Lines      296876   296893      +17     
  Branches    51128    51128              
==========================================
+ Hits       231655   231666      +11     
- Misses      58948    58953       +5     
- Partials     6273     6274       +1     

Files	Coverage Δ
static/app/gettingStartedDocs/node/nestjs.tsx	47.36% <ø> (ø)
static/app/utils/gettingStartedDocs/node.ts	56.81% <ø> (-4.41%)	⬇️

... and 3 files with indirect coverage changes

[priscilawebdev]

we need more reviews like this ... thank you 🚀