Update lilac config_machines.xml from version 2 to version 3.

In ctsm5.1.dev172 we updated externals for config_machines.xml from version 2 to version 3. Right now both are allowed, but I expect eventually only version 3 will be supported. So we likely will need to switch at some point. And it will be easier to support if it's more similar to the way machines are currently setup in ccs_config/machines.

@billsacks and I worked out what we think needs to happen. The machine_configuration directory that's created needs a top level config_machines.xml file that will look something like this:

``` xml

.*

$CIME_OUTPUT_ROOT/case/bld/cesm.exe
>> cesm.log 2>&1

```

beneath that will be a directory called "ctsm-build" for the LILAC generic machine with the normal contents of the config_machines.xml from before...

So something like...

```

Temporary build information for a CTSM build

$OS
.
.
.

```

I think the cmake macros file should also be in a cmake_macros subdirectory and named ctsm-build.cmake.