README.rst

These are mostly modelled on upstream nixos modules.
They are generally fairly configurable (they don't tend to hard-code paths, they can be enabled or disabled).
They don't know anything about morph (e.g. ``deployment.secrets``) or how the different grids are configured (e.g. ``grid.publicKeyPath``).
Each module here tends to define one service (or group of related services) or feature.
Eventually, all of these will be imported automatically and controlled by ``services.private-storage.*.enabled`` options.