Allow alignment formatting for Signature JotBlocks

Currently, the Signature JotBlock always places the saved signature in the center of the JotBlock area. The settings for Signature JotBlocks should be updated to allow left, center, and right justification of the final text (similar to the Alignment options on other JotBlock types). This would allow completed documents to look more logical. It's more common to sign a form starting at the left of your signing area, not in the middle, so electronic documents should reflect that as well.