Move networking intro to after image intro sections

[BretFisher]

Multiple people have given feedback that it makes more sense to learn container images before we learn Docker Networking. Restructure existing videos into new sections if possible, and move those sections into a pattern that looks more like this:

1. hands on with containers
2. basic image building
3. docker networking basics
4. docker volumes and bind-mounts
5. advanced images and multi-stage
6. compose v2