Add filter for D.va

[Innectic]

Fixes #198

[2Cubed]

We should not hardcode things like this.

Instead, the API should store a list of whitelisted (and blacklisted) texts that the bot uses in a similar method of checking. Then, when we need to add or remove whitelists/blacklists, we simply make a HTTP request, and Sepal distributes the updated list to bots without the need for even a restart.