update v17.6

"Discord Suggestions" is a short serie that will feature random prompts from
the #suggestions channel on our Discord Server.

The aim of this serie is to chop down the long suggestion list, without
having to wait a specific theme. 

Each batch will last 5-10 updates and is planned on a bi-monthly basis (~)

- Added a bunch of terrain props for the new grass+dirt tilesets
- Added a container (2 colors) and tons of junkyard props
- Updated the theme files with the new stuff

See you and happy game-making! :)