[Doc] Adding a friend projects section

[JeremyBP]

What kind of change does this PR introduce?
Adding a friend projects final section into the doc

What is the current behavior?
Doc doesn't talk about projects built ont top of Refit or using it to add some value

What is the new behavior?
Doc talks about project built ont top of Refit or using it to add some value

What might this PR break?
Nothing, just a doc update

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

Other information:
The PR about discussion #1832
Just thinking it could be usefull to let Refit's users know that some projects around there may help them building things with Refit and more :)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.79%. Comparing base (6ebeda5) to head (0be20aa).
Report is 117 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1856      +/-   ##
==========================================
- Coverage   87.73%   83.79%   -3.94%     
==========================================
  Files          33       36       +3     
  Lines        2348     2456     +108     
  Branches      294      346      +52     
==========================================
- Hits         2060     2058       -2     
- Misses        208      316     +108     
- Partials       80       82       +2     

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