Create frame on /donate with T-Shirt offer on $100 donation

small shirt “this year for a donation of 100$ get a t-shirt”
→ click bigger photo and explanation (how to claim your tshirt)

Feature Branch: web/17066+tshirtdonation

Parent Task: #16096

Original created by @u on 17066 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information