software/ors-amarisoft: slapos-render-config: Retarget currently generated enb.cfg and gnb.cfg to out/ors/

Besides ORS we will soon add other cases to enb.cfg generation. It will be
handy to clearly see what is what and to keep ORS case to be also alive and distinguished.

Prepare to that by emitting generated enb.cfg and gnb.cfg to out/ors/enb/ and
out/ors/gnb instead of just out. Name the file itself enb.cfg always to match
what happens for real in the SR.

There is no change to generated files - it is only renaming:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/ors/enb/enb.cfg
similarity index 100%
rename from config/old/enb.cfg
rename to config/out/ors/enb/enb.cfg
diff --git a/config/old/gnb.cfg b/config/out/ors/gnb/enb.cfg
similarity index 100%
rename from config/old/gnb.cfg
rename to config/out/ors/gnb/enb.cfg
```