add a way to get all terms and definitions out of gloss bot's database

[tmaybe]

Suggested by Matt Grieser (twitter), who says he'd like to see the full list for curiosity's sake, and possibly to display on a plain markdown page in github.

[tmaybe]

I've thought about providing a web interface or API to do this, but have been stalled on the need for authentication; don't want some random person outside of the people on my slack downloading our definitions.

Another option would be to have a new command that prompts Gloss Bot to upload its entire glossary to you as a file in Slack; that seems like it'd be an easier short-term solution.

[mattgrieser]

Thanks for adding the issue!

[lewisnyman]

+1 - even outputting a list in a Slack message would be a good first step

[LC1207]

+1