[6.13.z] ISS refactor - batch 2

[Satellite-QE]

Cherrypick of PR: #12347

Second batch of changes coming from the ISS evaluation

Introduced changes:

1. Added fixtures for importing orgs. These need to be new orgs so they don't reference the original org fixtures, which are used for export.
2. _enable_rhel_repo helper function was replaced by parametrized fixture and used through the module.
3. Using the fixture above three test cases were merged with test_positive_export_import_redhat_cv:

• test_positive_export_complete_version_rh_repo - was practically same as the first (export) part of the above case.
• test_positive_export_import_redhat_cv_with_huge_contents - same as the above case but bigger (rhscl) repo.
• test_positive_export_import_kickstart_tree - was a stub but now it's automated by the case above
  NOTE: The original plan was to test all KS and RHEL repos, however, due to the immediate download policy it would require more than the default 100G. So we need to decide if we want to test the real customer scenarios and go big, or use a small subset to stay bellow 100G.

4. Added RH repo to test_positive_export_import_default_org_view to address the PX comment.
5. Moved to SCA org as new default.
6. Some other minor changes like drift towards target_sat.cli* and docstrings on touched tests.

[Satellite-QE]

trigger: test-robottelo
pytest: tests/foreman/cli/test_satellitesync.py -k 'test_positive_export_import_default_org_view or test_positive_export_import_redhat_cv or test_positive_export_complete_library_rh_repo or test_negative_import_redhat_cv_without_manifest or test_positive_export_import_cv_end_to_end or test_positive_export_import_promoted_cv or test_negative_import_same_cv_twice or test_postive_export_import_cv_with_file_content or test_postive_export_import_ansible_collection_repo or test_positive_import_content_for_disconnected_sat_with_existing_content'