Use cocotb for HDL testing

[esynr3z]

Cocotb is mature enough to bring testing facilities into corsair, effectively abstract over specific simulator is used.

It will also allow to throw away our own launcher and "testing framework" reducing the amount of code need to maintain.

[esynr3z]

Planned to use cocotb for v2.0.0.a1 when Verilog generator is going to be implemented