export evaluation from default.nix and use it for docs

modules/all-modules.nix

@@ -0,0 +1,40 @@
+# Import all of the modules, used in the documentation generator. Not
+# currently expected to work in an actual configuration, but it would
+# be nice if it did.
+
+{
+  imports = [
+   ./base.nix
+   ./bridge
+   ./busybox.nix
+   ./dhcp6c
+   ./dnsmasq
+   ./ext4fs.nix
+   ./firewall
+   ./flashimage.nix
+   ./hardware.nix
+   ./hostapd
+   ./hostname.nix
+   ./initramfs.nix
+   ./jffs2.nix
+   ./kernel.nix
+   ./kexecboot.nix
+   ./mount
+   ./network
+   ./ntp
+   ./outputs.nix
+   ./outputs/vmroot.nix
+   ./ppp
+   ./ramdisk.nix
+   ./squashfs.nix
+   ./ssh
+   ./standard.nix
+   ./tftpboot.nix
+   ./ubifs.nix
+   ./ubimage.nix
+   ./users.nix
+   ./vlan
+   ./watchdog
+   ./wlan.nix
+ ];
+}