add "standard" module, which includes flashimage kexec & jffs2

most systems need most of these, so it makes writing the docs a
lot easier

doc/user.rst

@@ -12,13 +12,14 @@ and the services that you want to run on it. Start by copying
 ``vanilla-configuration.nix`` and adjusting it, or look in the `examples`
 directory for some pre-written configurations.
 
-If you want to create a configuration that can be installed on
-a hardware device, be sure to include the "flashimage" module.
+Your configuration may include modules and probably _should_
+include the ``standard`` module unless you understand what it
+does and what happens if you leave it out.
 
 .. code-block: nix
 
   imports = [
-    ./modules/flashimage.nix
+    ./modules/standard.nix
   ]
 
 

examples/arhcive.nix

@@ -31,10 +31,8 @@ in rec {
   };
 
   imports = [
-    ../modules/tftpboot.nix
+    ../modules/standard.nix
     ../modules/wlan.nix
-    ../modules/flashimage.nix
-    ../modules/kexecboot.nix
   ];
 
   hostname = "arhcive";

examples/extneder.nix

@@ -34,8 +34,7 @@ in rec {
 
   imports = [
     ../modules/wlan.nix
-    ../modules/tftpboot.nix
-    ../modules/flashimage.nix
+    ../modules/standard.nix
   ];
 
   hostname = "extneder";

examples/rotuer.nix

@@ -33,9 +33,7 @@ in rec {
 
   imports = [
     ../modules/wlan.nix
-    ../modules/tftpboot.nix
-    ../modules/flashimage.nix
-    ../modules/jffs2.nix
+    ../modules/standard.nix
   ];
   rootfsType = "jffs2";
 

modules/standard.nix

@@ -0,0 +1,10 @@
+{
+  # "standard" modules that aren't fundamentally required,
+  # but are probably useful in most common workflows and
+  # you should have to opt out of instead of into
+  imports = [
+    ./tftpboot.nix
+    ./kexecboot.nix
+    ./jffs2.nix
+  ];
+}

tests/min-copy-closure/configuration.nix

@@ -13,8 +13,6 @@ let
 in {
   imports = [
     ../../vanilla-configuration.nix
-    ../../modules/squashfs.nix
-    ../../modules/jffs2.nix
   ];
   config =  {
     services.sshd = longrun {

vanilla-configuration.nix

@@ -4,7 +4,7 @@ let
   inherit (pkgs.liminix.services) oneshot longrun bundle target;
 in rec {
   imports = [
-    ./modules/tftpboot.nix
+    ./modules/standard.nix
     ./modules/wlan.nix
   ];
   services.loopback = config.hardware.networkInterfaces.lo;