Settings for the sync server. These take priority over values computed from NixOS options.
See the example config in https://github.com/mozilla-services/syncstorage-rs/blob/master/config/local.example.toml and the doc comments on the Settings structs in https://github.com/mozilla-services/syncstorage-rs/blob/master/syncstorage-settings/src/lib.rs and https://github.com/mozilla-services/syncstorage-rs/blob/master/tokenserver-settings/src/lib.rs for available options.