Fix 70

[juliettelavoie]

Pull Request Checklist:

• pre-commit hooks are installed/active in my local clone ($ pre-commit install)
• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes Checking that we have all years  #70
• (If applicable) Documentation has been added / updated (for bug fixes / features)
• If a merge request has been made in parallel to this PR in xscen-notebooks, it is merged and the submodules have been updated.
• HISTORY.rst has been updated (with summary of main changes)
  • Link to issue (:issue:number) and pull request (:pull:number) has been added

What kind of change does this PR introduce?

• A more complete check of the file coverage in search. The previous test was only checking that the beginning and end of the period were present in the selected files. I added a test that counts the sum of hours in each files (according to date_start and date_end) and compares it to the amount of hours that should be in the given period (at the given coverage level, 0.99).

Does this PR introduce a breaking change?

Yes, search_data_catalogs will not return dataset with large holes in the data.

Other information:

We also need a check in extract_dataset. I suggested something in PR #68 based on the new argument ensure_correct_time.