Implement the set of tests for the time series forecasting quality

[nicl-nno]

Now the unit tests for the time series forecasting are quite formal and the low-quality predictions can still be fine in the test (because the benchmarks are too simple or the pass criteria are too weak).

It is necessary to implement a set of new quality-related tests for forecasting with atomic and composite models with a different structure.

[kasyanovse]

Может быть сделать интеграционный тест с pytsbe?