[proposal] rename `/src/server`

@wlach @hamilton @mdboom -- i think we should rename the "server" in `/src/server` -- it always trips me up that we have that and also a root level `/server` folder. here are some options to get the discussion rolling -- please flag your favorites and feel free to add your own ideas:

- nav
- nav-pages
- user
- user-pages
- home
- landing

i'm not really attached to any particular option, i just think we could make the distinction between the django server back-end and the nav/home/landing/whatevs front-end a bit clearer.

Start by comparing /src/server with the root-level /server folder to understand the distinction the proposal describes. Review references to /src/server and the suggested names before choosing a replacement with project stakeholders. Done means the naming decision is agreed and the directory can be renamed without leaving ambiguous references.

Written by the indexing model from the issue text.