Hanna Checker Ammonia HI784 tray

This is a modified version of the Alkalinity checker found here: https://makerworld.com/en/models/121501-hanna-saltwater-alkalinity-checker-holder#profileId-131041. Since I couldn't find any Ammonia checker tray out there, I decided to do this one. Prints win no supports at all.

I added trays for Reagent B and C, as well as extruded holders for pipettes to sit in comfortably and stably.