This reverts commit b1ff8e1a.

1.) Shutdown fix which allows us to see who requested to abort the simulation
2.) Properly initializing the NAS layer which previously was not happening for our simulation mode 5
3.) Changes in configurations to support the EPC(Have Melissa Verify these)

To match emane.

Checked with:
```
ps ax -o pid,class,priority,comm |grep RR
```

```
$ ps -eL -o pid,lwp,class,priority,comm | grep -E softmodem|oai:'
 6500  6500 RR  -80 lte-softmodem
 6500  6520 RR  -80 oai:enb-L1-rx
 6500  6522 RR  -80 oai:enb-L1-tx
 6508  6508 RR  -80 lte-uesoftmodem
 6508  6537 RR  -80 oai:ue-phy
 6508  6538 RR  -80 oai:ue-stand
 6509  6509 RR  -80 lte-uesoftmodem
$
```

To match emane.

Checked with:
```
ps ax -o pid,class,priority,comm |grep RR
```

To match emane.

Checked with:
```
ps ax -o pid,class,priority,comm |grep RR
```

This code was previously commented out.
But the `if` expression was wrong.

Revert unnecessary changes relative to origin/develop

Reviewed with Andrew

Rename our version to `UE_phy_stub_standalone_pnf_task`