GRIF-193: OSIDB 3.5.0 entities

[JakubFrejlach]

This PR:

• adds support for OSIDB 3.5.0 entities (Flaw CVSS, Flaw Package Versions, Affect CVSS)
• refactors OSIDB entities module into several smaller modules (1 module per 1 entity) for better navigation

[JimFuller-RedHat]

LGTM (was a bit involved due to the restructure) ... starting to wonder for update scenarios if we want to consider some kind of minimal mocking

[JakubFrejlach]

LGTM (was a bit involved due to the restructure) ... starting to wonder for update scenarios if we want to consider some kind of minimal mocking

Can you elaborate a little bit please?

[JimFuller-RedHat]

re mocking - the decision to not do mocking on reads was based on the fact that we test extensively in the services themselves ... mutation has less coverage and just 'out loud thinking' if we should consider mock tests for update scenarios ... just a random observation unrelated to this PR.