Drawable generic gate

[m-anwr]

Create a QGraphicsObject child class GatePart, create GateInput, GateOutput, and GateBody

[m-anwr]

@NourhanEssam
Very nice work 👍
I added some comments on some lines, Please review them and fix the problems.
If you can add the dragging option to the gates, please do, Otherwise feel free to fix the problems and merge back to the master branch.
Don't forget to follow the guidlines

[NourhanEssam]

I fixed the problems and added dragging option to the gates,
would you please review

[m-anwr]

@NourhanEssam
Good job, we will solve the overlapping problem later on,
You can merge for now 👍