skill and assessment view updates

- SkillQuestionBank table created (in order to tie together
skill-related questions and QuestionBanks
- Assessment questions can be added to Skills
- Assessment questions added to Skills have "valid answers" that can be
used later to validate if an Applicant is qualified for a specific job
- Assessment questions added to Skills now appear in "Assessments"
section (after Application section of public Kiosk)
- Assessment results are saved to database (for now, only one question
per skill is allowed for the current proof of concept phase)
- Added screenshots document these new features