* - Add controller for signature field, including buttons for save and reset
- Add library and style
* Add DB mapping for Signature field -> fix bug not saving
Add empty image, and auto load image when loading form
Add option for Signature field type on Doctype form
* Make field uneditable after submitting
* Remove console log and revert adding empty lines
* Update layout, remove edit mode/button, make save button compact. Refactor and use change event to trigger save.
* [cleanup] Signature Control
