Create a sample dataset for testing

[whonut]

Further to our discussion on the Discord, I took it upon myself to pull together a very small dataset just for testing purposes. There was a lot of repetition amongst the adventures we discussed including, so I pared it back a bit. It still includes a few nice things:

• An adventure with multiple authors
• Homebrew and official content
• Repeated phrases e.g. 'giant' that could be used to test simple text search.

The links for all the giant adventures are the same because they're part of the same module. It's JSON because I thought that might be useful for throwing them into the DB all at once. I'm happy to open a PR about this, I just don't know where it'd go.

File: adventures.txt