Module 2: Devstack (add screencasts!)

[sarina]

https://docs.google.com/document/d/1KuXU1kscRxce5esUuyOYRhuOjt4HyyGbGhdrLIusTC0/edit#heading=h.fnr38mrayz9l

Acceptance Criteria (feel free to create more to-do items as needed):

• [ ] Author all units in this subsection
• [ ] Tag a co-creator for review
• [ ] All revisions have been finalized - we're good to go!