Update docs to clarify a localhost setup using Docker for both 4CAT and DMI SM

[dale-wahl]

See issue here: digitalmethodsinitiative/4cat#483

I think the main confusion is between "local" and "remote" which actually will depend on how 4CAT is setup (is it using Docker volumes or a mounted drive) and the fact that 4CAT in Docker needs to have access to the host network (i.e. localhost may need to be host.docker.internal on Windows/Mac or otherwise the 4CAT Docker network needs to directly connect to the host network).