Tournaments: Add filter for 500 + 2000 gems tourney

[smlbiobot]

Feature request via Twitter https://twitter.com/TourneyAcademy/status/1024051956472586241

[ventajasgamer]

please

[6Sean]

@smlbiobot
There's a filter for 1K tournaments that's literally set up as an API endpoints. This one, if I'm not mistaken, would be a pull of all tournaments from the known or joinable tournaments endpoint of which there's no maxPlayer filter in the query string.

Probably a lower priority item - would be a good request back to the CR team to enhance the API for tournaments.