Update Donation Backend Schema for Multiples Items and Contact Info (Revised MVP

[scallait]

Update Make a Donation Backend Schema to accommodate multiple items as well as contact information. This corresponds to the following page on the Figma. (Revised MVP)

[peterchinh]

Update itemSchema name to be a list of String, and size to be a list of String (make sure the correct size is associated with the correct name) and test to make sure your updated itemSchema works.