Use sessions

[mrozbarry]

We should use the session management from node-lights to ensure no two computers are trying to control the lights at once.

Tasks

1. Update the api.* light functions to accept the token as a parameter
2. On run start, get a token* (const session = await api.sessionCreate()).
3. Store it somewhere, like /tmp/jest-lights/session.json. There is also a node_modules/.cache folder that we could take advantage of.
4. Set lights status during test
5. On run end, set the status light

• Token could be retrieved either by file or by API call

Other things

Related to this node-trafficlights ticket, being that we shouldn't have to shut off the lights from jest, we should rely on the server to shut it off after an appropriate amount of time.