notebooks with examples

[Nic30]

It was originally supposed to be a part of #123 but due insufficient time I extracted it as a separate tasks.

• notebook which will show how specific object are represented in HdlAst
  • hdl input -> hdlConvertor json
• notebook for translator api
  • verilog -> vhdl
  • vhdl -> verilog
  • optionaly
    • verilog -> pycocotb + example sim
    • verilog/vhdl function evaluation
    • verilog -> MyHdl + example sim
    • elaboration