Add bands model/endpoint

Bands are an array of strings in the database now, but that won’t work for very long.

There should be a bands model that foreign key to images. Bands should have the following information:

• band number (e.g. is this the first, second, third, etc. band for the image)
• name for band
• wavelength range field

Consult wireframes from @designmatty on the filters for bands to get a better sense of what this will look like

[notthatbreezy]

Yeah I think so - they should be part of the object for images

[notthatbreezy]

Good questions

• We’re not precluding a bands endpoint from ever existing, but the first point is good. I think the expectation is that the PUT requires the full resource. If we add a PATCH method it will handle the case where only part of an image comes back
• We’ll need to return bands with the image I think. If it turns out to be too cumbersome we can remove it potentially, but the scenes endpoint is already paginated so we should be OK for now. This isn’t an uncommon issue with APIs like this, but it’s something we’ll have to watch out for I think.