feat: Track outbound links in docs site.

[sidharthv96]

📑 Summary

View conversion rates on promotion banner.

📏 Design Decisions

Unlike mermaid.live, there is no user provided links in mermaid.js.org.

So we can track the outbound link clicks without leaking any user data.

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[codecov]

Codecov Report

Merging #5116 (770fc41) into master (78c44bf) will increase coverage by 3.01%.
Report is 1 commits behind head on master.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5116      +/-   ##
==========================================
+ Coverage   75.29%   78.31%   +3.01%     
==========================================
  Files         164      164              
  Lines       13820    13820              
  Branches      693      693              
==========================================
+ Hits        10406    10823     +417     
+ Misses       3243     2847     -396     
+ Partials      171      150      -21     

Flag	Coverage Δ
e2e	83.90% <ø> (+3.75%)	⬆️
unit	42.94% <ø> (ø)

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

see 15 files with indirect coverage changes

[aloisklink]

Looks good to me!