edit runparams model to account for multiple product_id's in a single run

[kdionisio]

Currently hem_app_runparams is set up such that each run (each row of the table) is associated with a single product_id/category_id. However due to the length of run time for the model, we will be putting multiple product_id's into a single run (e.g. deodorant gel, deodorant spray, will all be grouped into a 'deodorant' run. We previously talked about a 'linker' table so that, for each run, you provide in the linker table all product_id's included in that run. However in this case we would need to figure out which of the product_ids would appear in the 'by product' drop down menu on the input page.

Note we could have a linker table to list all product_ids included in that run (eg deodorant gel, deodorant spray, deodorant solid), and then create a new product_id associated with 'deodorant all', where the latter product id is what is included in the drop down menu on the input page)

Move category and products to linker table and add a title in run_params that will populate the dropdown

[kdionisio]

@dmlyons2 Note, please do not make changes to the database that will force removal of the data in the dose table (or cause the demo on Newton not to work) until after the 7/12 meeting with Jeff F. I will not have time to re-load all of that data before the meeting with Jeff, and I would like the demo version working for that meeting if possible!