Simplify the configuration asm generator, phase 2

After the split, it makes sense to start simplifying every individual generator. This is partially a research issue. Exactly what to do is not clear yet.

Some context: classes in package org.apache.ignite.internal.configuration.asm are pretty big and complicated.  InnerNodeAsmGenerator is almost 2000 lines long.

How can we make it simpler? Better naming, more comments. Inner node generation can be split into multiple files, because it also handles polymorphic implementations.

In some cases I would change the generation itself. For example, generated methods in polymorphic instances have the same implementation as in original inner node instead of simply delegating the execution to inner nodes. It affect both performance and the code of the generators in negative way.