Simplify and linearize priorities of loading Global and Scene assets

[mikhail-dcl]

Problem

We don't have a straightforward mechanism to control the order of loading of assets:

• Mix of Global World entities and Scene entities is hard to control
• No strict mechanism to tell what must be loaded first and how it's distributed between different partitions: Scene Assets, LODs, Roads
• Loading budget (WebRequests budget) is not shared between all asset types
• Behavior is generally non-comprehensible and distributed between different systems on different levels

The aforementioned leads to:

• Distant assets can be loaded first
• More priority ones from the UX perspective can linger for a while
• The system is effectively unmodifiable
• Chaotic CPU budget consumption
• Chaotic Loading budget consumption
• DeferredLoadingSystem exists in multiple copies and is not capable of grasping all the intentions available to sort them

Other ideas:

• Split colliders and regular meshes in the AB converter into 2 separates bundles. It will allow to prioritize bundles with colliders

[m3taphysics]

Should be fixed by: #1877