Fix reply to comments and settling comments

[tj-mai]

the commentscontroller disappeared, including the SaveAnswer method , you can still create new comments but you can't answer to it.

You can't mark comments as settled either

steps:

1. go to a question with answerbody (topic > learning tab)
2. click on comment bubble in the bottom right corner of the question details
3. can't answer to a comment and can't close discussion

problems:

• add answer comment to discussion does not work
• settling and unsettling / marking comments does not work
• not every discussion can be answered, missing answer component
• answering on an open ( not collapsed ) discussion crashes the page
• answering on a closed ( collapsed ) discussion works, but opening afterwards also crashes the page
• comment count on the comment speechbubble icon (answer question details below question stats) does not show the correct number

acceptance criteria:

• saving and settling answers/discussions
• send and receive email or message on answers/discussion (on question or discussion itself) might have to update link to ${first available topicName}/${topicId}/Lernen/{questionId} > auto opening comment, also use $urlHelper.getTopicUrlWithQuestionId()