Support Arrays of data for time_series

[twojtasz]

Issue https://github.com/uber/xviz/issues/417 wants to associate arrays & vectors of data with other streams. This is done currently with the id linking in the application, but we only support scalars in time_series

We should support arrays of values. Possibly even dictionary? not sure about this one.

[twojtasz]

@jlisee will want your thoughts on this

[jlisee]

@twojtasz sorry for the late reply but the we already do this through variables. It would look like:

{
  "base": {
    "object_id": "foo"
  },
  "values": {
    "doubles": [1001.3, 1002.3, 1003.3]
  }
}

I will mention this on that issue as well.

Looking at the code the variable builder has needed method, but it's not in the docs yet:

https://github.com/uber/xviz/blob/d931a3993138be61df79ae551b9ab3ee9053e60c/modules/builder/src/builders/xviz-variable-builder.js#L53-L57