Restructure code for feedback session questions (JavaScript) #2748

Fixes #2748 

Minor organization, moved code for specific question types together and to the bottom.

So far, here is a list of steps to be done for adding a new question type:


Java
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Add and implement the following:
- Feedback<question type>QuestionDetails.java - extends FeedbackQuestionDetails
- Feedback<question type>ResponseDetails.java - extends FeedbackResponseDetails

FeedbackQuestionType.java
 - Define new question type
 - Add cases in getFeedbackQuestionDetailsInstance() and getFeedbackReseponseDetailsInstance()


JSP
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Nothing to do here...

JS
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common.js
 - Add in constants for feedback question typename (Format: FEEDBACK_QUESTION_TYPENAME_<question type>)

instructorFeedbackEdit.js
 - Hide new question form in hideAllNewQuestionForms()
 - Add logic in prepareQuestionForm() to prepare new question form
 - Add logic in enableQuestion() if necessary

feedbackSubmissionsEdit.js
 - Add logic if necessary


Tests
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Add test cases in:
FeedbackResponseDetailsTest.java
InstructorFeedbackQuestionAddActionTest.java
InstructorFeedbackQuestionEditActionTest.java


Add and implement the following
 - Feedback<question type>QuestionUiTest.java
	- Add test class to testng.xml
	- Test add/edit
 - Test Submit (StudentFeedbackSubmitPageUiTest.java) ?
 - Test Results View by adding in data to existing json files