Split sdba

[coxipi]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #xyz
• Tests for the changes have been added (for bug fixes / features)
  • (If applicable) Documentation has been added / updated (for bug fixes / features)
• CHANGELOG.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?

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Does this PR introduce a breaking change?

Other information:

We must remove sdba-warning.yml , yes?

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Warning

This Pull Request modifies the SDBA module.
The SDBA module is gradually being deprecated in favour of the xsdba package.
Any changes to xclim.sdba should be made in https://github.com/Ouranosinc/xsdba

[coxipi]

Should have I kept the sdba tests? now I think of it, it would be useful to have them to test xsdba integration in xclim.

[Zeitsperre]

Should have I kept the sdba tests? now I think of it, it would be useful to have them to test xsdba integration in xclim.

We kept the tests around for the GIS component for about a year, despite there being little reason for it. I wouldn't suggest us doing that again.

It might be worthwhile to only keep the tests that rely on both xclim and xsdba as an assurance? W would also test to make sure that the proper warnings/errors are being emitted in the event that xsdba is not installed.