Drag item from components list to canvas

[m-anwr]

User should be able to drag an object to the canvas and the result should be a square centered in dropping place

[m-anwr]

@Eslam-Samir Why the first dropped gate alwayes goes to the center?
Please fix this

[m-anwr]

@Eslam-Samir Try the following:

• open my computer
• drag a folder/file
• drop it on the canvas
• a gate should be drawn

[Eslam-Samir]

@Tootis
1- the first dropped gate doesn't go to the center, but the graphics view always centers the graphic scene by default i think you should review this point.
2- fixed dragging and dropping folders/files issue.

[m-anwr]

@Eslam-Samir

• You did good but I think you can leave the ui as is and just use the grid layout to add the "ComponentsTab" to it
• the initialization now can be moved to the components tab class