lineBuff and dbuff of DebugDraw can be converted to std::optional

[ghost]

It should be quite simple task, but replacing usages can require some work.

[ArtemPopof]

What is a purpose of this changes?

[ghost]

They are not moved even once, when engine is running. So it's better to use static allocated memory and improve caching.

Also operating on objects is nicer than on ptrs.