FI logos: allow OCP admins to upload a FI logo, and show it in their credit products

[yolile]

Right now the quick implementation was to add the logo in the front end as an asset and only store the file name in the FI form. The proper implementation would be to upload the image as part of the FI form.

[jpmckinney]

In advance of the frontend changes, we can already make the db changes, and manually run a SQL query to add images. This would reduce coupling between logo_filename and files in git in the frontend.