[Misc] Encapsulate logical gates in custom gates

[amirebrahimi]

It would help with visualization I think if we encapsulate logical X, Y, Z and stabilize with custom gates, so that circuit visualizations are more reasonable. Then, if a user wants to decompose the circuit further they can to see the same circuit visualizations that we currently have.

[Phionx]

This is semi-related to this issue : #44

Also, it would be cool if we could show the internal gates that compose a logical X gate (for example) and also denote that these gates constitute an overall logical X (i.e. add in some text over the barrier constrained region with the logical X gates).