Custom graph model optimization - refactored version
To achieve to applicability of the gp_optimizer to structural learning of custom graph-based models, the following changes are implemented:
- Graph/GraphNode as prototypes for Chain/Node
- OptGraph/OptNode as obtimisation object
- adapter to converrt Chain to OptGraph and back
- simplified example of custom model learning
- custon constraints customization for implemented
- custom mutain and crossover can be used
Now gp_optimizer can be used for any graph-based optimization problems.
Proposal: rename Chain to Pipeline
Old version: https://github.com/nccr-itmo/FEDOT/pull/269