Separate core (not dependant on anything) SDK logic from user code dependant SDK logic

[FranjoMindek]

Part of #2247
This issue addresses point 2.2. from the following comment: #2247 (comment)
Blocked by: #3517

We should:

1. Research which parts of SDK depend on the user code.
2. Refine the issue with information above.
3. Separate core SDK logic from user code dependant SDK logic.

Estimate: 3-6 days