feat(openSSF scorecard): introduce CI + badge

[AugustinMauroy]

Adding openSSF scorecard. It's add CI and badge. Also action allow us to have an UI to see what is wrong or good.

Fixes #211

[madolson]

@bjosv Does this seem right to you?

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 69.83%. Comparing base (315b757) to head (769010b). Report is 17 commits behind head on unstable.

:exclamation: Current head 769010b differs from pull request most recent head d9fdec2. Consider uploading reports for the commit d9fdec2 to get more accurate results

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable     #472      +/-   ##
============================================
+ Coverage     68.90%   69.83%   +0.92%     
============================================
  Files           109      109              
  Lines         61793    61791       -2     
============================================
+ Hits          42579    43150     +571     
+ Misses        19214    18641     -573     

see 37 files with indirect coverage changes