ORKConsentSignatureController: refactor constraint code
ORKConsentSignatureController: refactor constraint code

- Make most constraints static and lighten updateConstraints.
- Add constraints by activation.

weijentu/ResearchKit,DrGo/ResearchKit,boland25/ResearchKit,oliverschaefer/ResearchKit,boland25/ResearchKit,YuanZhu-apple/ResearchKit,KaiCode2/ResearchKit,cornelltech/ResearchKit,chb/ResearchKit,shazino/ResearchKit,DrGo/ResearchKit,mluedke2/ResearchKit,mluedke2/ResearchKit,umerkhan-apple/ResearchKit,weijentu/ResearchKit,mluedke2/ResearchKit,shazino/ResearchKit,danoli3/ResearchKit,YuanZhu-apple/ResearchKit,KaiCode2/ResearchKit,umerkhan-apple/ResearchKit,jarrelscy/ResearchKit,allen7wang/ResearchKit,jeremiahyan/ResearchKit,danoli3/ResearchKit,jimmyti/ResearchKit,jarrelscy/ResearchKit,weijentu/ResearchKit,allen7wang/ResearchKit,YuanZhu-apple/ResearchKit,chb/ResearchKit,chb/ResearchKit,jeremiahyan/ResearchKit,cornelltech/ResearchKit,jeremiahyan/ResearchKit,oliverschaefer/ResearchKit,umerkhan-apple/ResearchKit,jimmyti/ResearchKit,QuintilesRK/ResearchKit,jimmyti/ResearchKit,QuintilesRK/ResearchKit,YuanZhu-apple/ResearchKit,QuintilesRK/ResearchKit,boland25/ResearchKit,weijentu/ResearchKit,shazino/ResearchKit,oliverschaefer/ResearchKit,md0u80c9/ResearchKit,jarrelscy/ResearchKit,danoli3/ResearchKit,cornelltech/ResearchKit,md0u80c9/ResearchKit,md0u80c9/ResearchKit,chb/ResearchKit,allen7wang/ResearchKit,DrGo/ResearchKit,md0u80c9/ResearchKit,boland25/ResearchKit,KaiCode2/ResearchKit,oliverschaefer/ResearchKit