Pedigree PNG file rendering and serving

[mikkonie]

Rendering germline sample sheet pedigrees is currently done by embedding SVG data directly into the template. We should instead render these into PNG files, with larger versions of the files downloadable.

The code is already there but commented out: PNG files can be generated using cairosvg. However, we must first decide on how to serve the data in production.

• Django doesn't allow serving media files directly from its server in production
• Whitenoise can serve static files, but these are not static as they change each time a germline sample sheet is updated
• A popular approach is to set up a separate server (usually Nginx) to serve the files
• Other ways to do it = ???

Once we decide on the approach, it should be a relatively quick and minor task.

[mikkonie]

moved from omics_data_access#57

[mikkonie]

Likely solution: develop a view which renders a .PNG file as result, call that from the parent template. Should be easy and simple!

[mikkonie]

removed milestone