Improve product filtering through REST API

[dfaller]

Add the following fields for filtering through the products REST API:

job_output (char field, the output name from the job interface)
recipe_id
recipe_job (char field, the job name of the job within the recipe definition)
batch_id
data_started
data_ended
source_started (the earliest start time from all source files)
source_ended (the latest end time from all source files)

Any fields that don't currently exist in scale_file need to be created nullable (so the migration is fast). All new fields except job_output and recipe_job should be indexed. Update logic so all of the above fields are populated correctly when a product is saved.

Note that the new filtering should be added to both the /products/ and /sources/{id}/products/ APIs.

Also create a new mode called JobInput (table job_input) with columns job (Job model), job_input (char), input_file (ScaleFile model), created (timestamp with tz), all not nullable. Update Scale logic so that this table is populated when input data is attached to a job.

Also add new nullable recipe_input field (char) to the RecipeFile model. Update Scale logic to populate this when an input is added to a recipe.

[dfaller]

Quick little addition: update the saving of parse results so that if only one of data_started and data_ended is provided and the other is none, Scale saves the provided timestamp as both data_started and data_ended.

[dfaller]

One final addition: add recipe_type to the list of new fields as well.

[mikenholt]

is_superseded and superseded need to be added to the base products sterilizer so it is returned by the API.