Eval Form - Save button implementation

[stepchud]

What/Why

This task will enable the user to Save a valid evaluation form.
It must be completed after (is blocked by) #162, #163

Acceptance Criteria

• Save validates all form fields
  • Form start_date is automatically set to the Challenge Phase phase.end_date
  • Form end_date must be after the Form start_date
  • Form end_date is always editable
  • Total of all Criteria for Weighted Scoring must add up to 100
  • When the evaluation period starts, form fields are not editable (except end_date)
• If the form passes validation it is persisted to the DB
• If the form passes validation, the confirmation page is displayed to the user

Disregard the following if this work does not include any UI changes

• WAVE screenshot
• Automated a11y tests (axe-rspec specs)
• Keyboard accessibility (tab navigation, form interactions)
• Responsiveness at desktop and mobile

Out of Scope

[r-bartlett-gsa]

@stepchud

Suggested rewrite of the AC:

• 'Save' validates all form fields
• Evaluation start date is Challenge close date
• Evaluation end date is after start date
• Evaluation end date is always editable
• Total of all Criteria for Weighted Scoring must add up to 100
• If the form passes validation a confirmation page is displayed
• The form fields, expect end date, are not editable between evaluation period dates

[cpreisinger]

[stepchud]

Fixed in #219