WIP: use sccache

[mcocdawc]

Description

Try sccache in ecflow.

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

🌦️ >> Documentation << 🌦️
https://sites.ecmwf.int/docs/dev-section/ecflow/pull-requests/PR-324

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 49.61%. Comparing base (02a695f) to head (83e2114).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #324      +/-   ##
===========================================
- Coverage    49.63%   49.61%   -0.02%     
===========================================
  Files         1238     1238              
  Lines        97521    97521              
  Branches     14876    14876              
===========================================
- Hits         48401    48386      -15     
- Misses       49120    49135      +15     

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