[WIP] feat: remove content access mode cache

[DuckBoss]

This patch aims to remove references to the 'ContentAccessModeCache' and refactor/simplify related code that
checks this cache since entitlement is being phased out and SCA will be the only content access mode.

Resolves: CCT-619

[ptoscano]

Thanks for the PR! It generally LGTM, there are a couple of things to fix.

---

Regarding the failure of CertSorterTests::test_missing_installed_product: that test is practically useless now.
The reason for this is:

• in the test setup, StubContentAccessModeCache was set up for CONTENT_ACCESS_MODE_CACHE: since that stub cache had no content, the comparison in is_simple_content_access() against "org_environment" always returned false
• is_simple_content_access() now stops using CONTENT_ACCESS_MODE_CACHE, so it always returns true now (thus SCA)
• ComplianceManager (from which CertSorter derives) fills unentitled_products based on the compliance information, which is an entitlements-only feature (see ComplianceManager._parse_server_status(), the code guarded by is_sca in particular)
• hence CertSorter.unentitled_products is always empty in SCA mode

In case you are wondering: yes, the other tests that check CertSorter.unentitled_products in any way are sort of dead now. To make them working again, ideally is_simple_content_access() should be mocked/patched for them to return false (and thus ensure things work in entitlement mode). OTOH, dropping compliance bits is a potential further step.

---

Also make sure to remove the old cache file on upgrade: see the existing code in %posttrans that removes an old cache. Simply remove the dropped cache there as well.

[ptoscano]

To make them working again, ideally is_simple_content_access() should be mocked/patched for them to return false (and thus ensure things work in entitlement mode).

Or, even better, do the same approach that CertSorterSCATests does: patch is_simple_content_access() in setUp() to always return false, so all the tests in CertSorterTests work again in entitlement mode.