Katie Holmes and Jason Bard Yarmosky have officially soft-launched their romance on Instagram. The actress re-shared multiple Instagram Stories posted by the artist, including a sweet photo he seemingly snapped of her, on Thursday — one month after rumors first swirled that the two were dating. In one of the pics, the “Dawson’s Creek” alum stunned in a yellow, silk ensemble and metallic heels as she posed in a barn and flashed a smile. Another photo appeared to be taken at an art show the couple attended together, while the third pic featured a gorgeous sunset. Holmes’ social media move comes nearly a month after Page Six exclusively…