Don't load filtered-out parents eagerly on every Object.access

[psrok1]

Your checklist for this pull request

• I've read the contributing guideline.
• I've tested my changes by building and running the project, and testing changed functionality (if applicable)
• [ ] I've added automated tests for my change (if applicable, optional) (already covered)
• [ ] I've updated documentation to reflect my change (if applicable) (no changes)

What is the current behaviour?

There is definitely too much magic there that is quite ineffective. When object has lots of parents, every Object.access() that is called in almost every object endpoint will eagerly load all parents and all its tags even if they're not used by the endpoint.

What is the new behaviour?

Replaced eager loading with property accessible_parents that makes a query when requested. It is then called by proper schema fields.

Other functions that are relying on user's view of parents are already using dedicated query instead of object.parents direct relationship access (e.g. search additionally filters out objects using g.auth_user.has_access_to_object)

Test plan

Security checks covered by automated tests. Performed manual check if everything works properly.

Closing issues