Adds description for test EPA-01

### \[EPA-01\] EPA+SR-IOV without underlay

TODO: Under ellaboration.

As a precondition for this test, please make sure:

1. Your VIM has an accessible management network (in this case called "<VIM_MGMT_NET>")

2. Your VIM has the appropriate test image, in this case `ubuntu18.04`.

3. Your VIM uses a phuysical dataplane network (for instance, it was created with `dataplane_physical_net: physnet2` in its configuration).

Onboard the following packages on OSM ([refer to this repo for OSM packages](https://osm.etsi.org/gitlab/vnf-onboarding/osm-packages)):

```bash

osm nfpkg-create hackfest_basic_sriov_vnf

osm nspkg-create hackfest_basic_sriov_ns

```

Instantiate the NS:

```bash

osm ns-create --ns_name epa_01-epa_sriov_test --nsd_name hackfest_basic_sriov-ns --vim_account <VIM_ACCOUNT_NAME>|<VIM_ACCOUNT_ID> --ssh_keys <KEY1_PUBKEY_FILE> --config '{vld: [ {name: mgmtnet, vim-network-name: <VIM_MGMT_NET>} ] }'

```

Wait for the VM instante to be up and SSH into it (credentials are ubuntu/osm4u).

After that, check an Ethernet device is enabled on the VM interfaces (you should see it as "Ethernet controller" istead of "Virtio" on the devices list):

```bash

lspci | grep "Ethernet controller" | grep -v "Virtio"

```

Finally, delete the NS and the onboarded packages:

```bash

osm ns-delete epa_01-epa_sriov_test

osm nsd-delete hackfest_basic_sriov-ns

osm vnfd-delete hackfest_basic_sriov-vnf

```

### \[EPA-02\] Support for additional EPA capabilities