Meetups: Set up procedure to get swag

[mjang]

To help promote Write the Docs, meetup leaders frequently request swag for their events.

Ideally, they'd collect WTD swag from conferences that they attend, Where this is not possible, we need a procedure for how they might get inexpensive swag, e.g. stickers. Possible sources:

1. People on the WTD staff who have access to such swag
2. Some self-service portal where meetup leaders can order such swag for some "nominal" cost