Switch Actions organization from ecmwf-actions to ecmwf

[recmanj]

Update CI/CD workflows as ecmwf-actions actions have been moved to ecmwf organization.

[FussyDuck]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.17%. Comparing base (ba1da1a) to head (f46c66c).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop      #60   +/-   ##
========================================
  Coverage    51.17%   51.17%           
========================================
  Files           58       58           
  Lines         4782     4782           
  Branches       449      449           
========================================
  Hits          2447     2447           
  Misses        2335     2335           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.