Process date values in spacecmd api calls (bsc#1198903)

[ycedres]

What does this PR change?

Inside the spacecmd command-line interface the api function was showing an error when trying to pass dates with the -A argument. Now it parses the dates and calls the API endpoint with a suitable parameter type.

An example:

api -A "sle-product-sles15-sp3-pool-x86_64,2022-05-20,2022-05-25" channel.software.listAllPackages

GUI diff

No difference.

• [x] DONE

Documentation

• No documentation needed: only internal and user invisible changes

• [x] DONE

Test coverage

• No tests: bugfix

• [x] DONE

Links

Fixes #1198903 Tracks https://github.com/SUSE/spacewalk/issues/17671

• [x] DONE

Changelogs

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• [ ] Re-run test "java_pgsql_tests"
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• [ ] Re-run test "javascript_lint"
• [ ] Re-run test "spacecmd_unittests"

[agraul]

@ycedres can you please add tests?