[FEATURE] support multi-source satelittes

[graciegoheen]

Is your feature request related to a problem? Please describe.
I currently get this error when I try to supply multiple sources to the sat macro The name argument to ref() must be a string, got <class 'list'>

Describe the solution you'd like
I want to create a satellite that unions together multiple sources.

Describe alternatives you've considered
Could create a view that first unions together all sources, but that seems like an unnecessary additional layer.

Additional context
Similar to #131

[DVAlexHiggs]

Hi,

In the data vault method we do not create satellites from multiple sources. This is what hubs and links are for, as these are the integration points.

The data is integrated in hubs and links and satellites off of these objects, and the satellites then contain the descriptive information for that integrated data.

If you would like more information about this please take a look at online resources specified here.

Please feel free to browse the Data vault User group orums and ask this question here if you would like input from industry experts as well as the AutomateDV team in further detail!