Use GeoDjango for storing geographic data

[david-code]

Description

We currently store information about Site as two separate latitude/longitude columns. It would be better to store the information using the GeoDjango PointField type. Because we don't currently use GeoDjango, it would be good to follow any parts of the GeoDjango Tutorial that are necessary for setting up the plugin. (We already include postgis in our database, so that part is not necessary).

For the purpose of doing only one thing at a time, the GraphQL Site Node endpoints should continue serving latitude, longitude fields on the Site so we do not have to update the front end (we might want to change this later).

Tasks

• [ ] Set up GeoDjango config
• [ ] Change Site model to use PointField (name of the field should probably be coords or something like that) and remove old latitude and longitude fields
• [ ] Make sure GraphQL SiteNode still returns latitude, longitude instead of the new point field

[shrouxm]

i'm removing the lpks label/project and backlogging this as there's not much immediate benefit and there might be different ways of achieving future potential benefits of doing this. but there's no downside besides the work to make it happen and it comes with minor benefits so i won't close it