I've never heard it in BE, but that doesn't mean very much - I doubt if I move much in the circles where it might be used: to hustle is, among other things, to try to sell one's body. Some people talk about the hustle and bustle of everyday life. The Urban dictionary might tell you what it means.
the hustle could actually mean drug dealing, selling cars, or any ordinary job. Normally the term refers to illegal solicitations such as drugs or sex. For instance a pimp could be reffered to as a hustler. The term grind is also used in the same way. "How's life in the hustle?" Means "how is your work life?" where I come from. This is definite slang, and I doubt it will ever become a fixed expression.