Old Navy will open its first Big Island store by the end of this year in Hilo's Prince Kuhio Plaza, officials with mall owner General Growth Properties confirmed to PBN on Wednesday. The retailer, which will carry an array of men's, women's and children's clothes, will occupy a 15,600-square-foot space next to Pier 1 Imports and employ about 80 people once it opens by the holiday season. Prince Kuhio Plaza spokeswoman Robyn Gee Tucker said Old Navy's move into the mall comes on the heels of Pier…