CMA Create Context

This shared module ported from v2 code cmaCreateContext. Removed all the snowplow related code. The mobile session needs to be added as a part of the code later. This creates the mobile_context, the uids, and adds additional session information to the payload. Relies on the typical body format style of:

{
  action: { ... },
  state: { ... },
  payload: { ... }
}
Additional contexts can also be provided where available.

Usage:

const cmaCreateContext = require('@nordstrom_clickstream/ato-cma-create-context');
...
const result = cmaCreateContext(body, session);

Return: 
{
  uid:{},
  client_session:{},
  mobile_context:{}
}