[HandshakeSimulator] Draft attempt inspired with the example

[Liudmila-Paskonova]

• Some suggestions for classes definitions
• Several components implemented (Constant, Extsi, End, Return, Muli, Sink, Source). Maybe there're some mistakes in the architectures, I'll recheck it later
• Simple circuit for the example easy_sum

Class Circuit represents the circuit and includes the set of components and the set of channels (with corresp. wires). The channels are stored in the memory -> all the components have smart pointers, pointing on it, that's why, if the particular component updates some value, other components which are connected to the same channel, can see it, and additional memory isn't wasted. Everything is built around abstract classes - they help create containers that can store whatever we want.

Not implemented yet:

1. Multi comps inside the arch (e g muli) - working on it
2. inputs/outputs for the circuit - forgot about it:))
3. Clock changes, now exec's modelling only reset
4. Writer/ Reader

[lucas-rami]

Superseeded by #127.