Support Request: "Comment {Date,Author}" on frontpage

Originally, there was a regression introduce in my recent changes that "Comment Author" column was always empty.

This MR contains some more refactoring for "Comment Date" and "Comment Author" columns:

On the visible side, "Comment Date" column has been simplified, it used to show "hour:minutes" if the message was posted today, and "year/month/day" if the post was older. It's now a simple date time field (using Base_viewCRMFieldLibrary/my_event_start_date), for consistency.

On the implementation side, they now use existing SupportRequest_getCommentPostListAsJson script, which simplified code a lot. That script was also renamed as SupportRequest_getCommentPostList, because it's no longer returning JSON.