(maint) Use named volumes in compose where possible

[Iristyle]

• docker-compose supports named volumes, which are different than the
  bind mounts that have been used thus far

  bind mounts expect that the host directory exists on disk and their
  behavior is a bit different, and is discussed in the docs at:

  https://docs.docker.com/storage/bind-mounts/

• While LCOW is happy to support both volumes and bind mounts, support
  from the platform is a bit different. Specifically it appears that
  bind mounts properly support hardlinks (necessary during Postgres
  startup), while volumes do not. An issue has been filed to track that
  issue at LCOW: Docker Volumes should grant FullControl to associated vmwp.exe process user hosting container (was: CreateFile access denied) moby/moby#39922 (originally filed at LCOW: Docker Volumes don't support some fs operations that bind mounts support - CreateFile access denied microsoft/opengcs#337)

• Switch all volumes to named, except for the one Postgres data volume
  which must remain a bind mount

[nwolfe]

I'm curious how users will respond to this change, since it's breaking, and requires them to put things into a new directory that takes some extra work to figure out.

I have some hesitation around whether it's okay to be hand-modifying these directories directly from the host machine, but nothing concrete to go on really.

It seems the docker docs around volumes have changed, so maybe this is actually okay!

I do like this better than what we had before.