Add DS files for C++

[restrictedCodex]

add Stack data structures into the code base by creating a new folder

[ShubhamSj07]

#15

[anujjain5699]

Please assign this issue to me

[ShubhamSj07]

Please assign this issue to me

Pls go ahead @anujjain5699 🙌🏻✨

[Roshan5401]

I am good at dsa in cpp please assign me this under hacktoberfest i would like to contribute.

[restrictedCodex]

@Roshan5401 please make a PR we will assign it to you

[shahidcode]

Please assign this issue to me