adding view for uploading CSVs
adding custom file list template and placeholder
Adding missing CSRF token to inline delete
disabling actions, basic file validation
removing unused importer file
better CSV import modularization

The data_importer now has an enhanced role - it performs all the
filtering and normalization necessary to get correct RadRecords.  With
that in mind, the data_importer is now responsible for generating
RadRecords from the provided CSV file.

I also removed a bunch of unused stuff from the data_importer - I think
a lot of it was originally there to create categories, which is now
automatically handled by db_fun.

As part of this, I also generalized how we're filtering out invalid
column names.  Instead of just looking for an 'id' column and removing
it if it's there, we now grab a list of the fields available for the
RadRecord and filter out anything that's not in that list.
getting resource preview working
improving styling of preview
adding checkbox for each row
adding duplicate detection

To abstract away some of the checks, each resource is now wrapped in a
dictionary that contains metadata such as the row index, the validity of
the resource, and if it's a duplicate.
styling tweaks
starting to fill in POST
making category creation optional
standardizing db_fun methods to work with sessions
fixing db references, existing category searching

In the event that we're lazily-creating a record (meaning we don't care
about dupes), we'll cut to the chase and just create a new one.
successful resource importing!
making list template nicer
removing icon class/tooltip
removing icon since we have text
removing download link from each file name