Add missing VLC instructions

from our old guide:

```md

## VLC

VLC can record and display the received video. To receive the video video from companion, it's necessary
to go in: **Media** → **Open Network Stream** → **http://192.168.2.2:2770/vlc.sdp** → **play**.

Note: It's possible to configure the caching size of VLC to allow a faster time response from the video, this configuration
is done under: **Media** → **Open Network Stream** → **Show more options** → **Set caching to a number around 200** → **play**

The record and conversion can be done with the save menu: **Media** → **Convert** → **Network** → **Convert / Save** → **Select format** → **Select destination** → **Start**.

```

Locate the ArduSub guide page where video reception instructions belong, then add the supplied VLC section and its referenced images under /images/vlc/. Verify that the Media menu steps are readable and that all six image links render correctly in the documentation.

Written by the indexing model from the issue text.