DNSCHAT-1: Write-up High Level Design

Write up the high level design - worth including the current thinking on how the communications will be structured, though it'll likely need improving/tweaking as the system is built.

The chat client needs to include

- Encryption (Symmetric for simplicity - this is only a PoC)
- (Possibly) support for multi-user chats (as opposed to one on one)

Should definitely use Scapy to capture incoming messages as it gives flexibility in where the client can be run (i.e. rather than having to be the DNS server, it can be run on the DNS server or anywhere where interception of the queries are).