What does the quote ''It takes a village'' mean?

It means that a child does not just grow up within a home, where there may be a single parent or a combination of parents, but a child will grow up in a community, a village, and that a child will not grow up just in a home but in a social world with input and understanding from the village. Regardless of the child's upbringing, the child belongs to and is shaped by the community.
It means that a child is influenced by her environment. If the neighborhood she lives in has a bunch of drug users, then she will be more likely to be a druggie. Parents and siblings aren't the only people in her life, so they're automatically not the only ones who have influence on her.

It's common sense, really. Unless you keep your kid in a cage, then they are going to interact with other people. They're going to be exposed to the media.

It literally takes a village to raise a child.