[Discussions] Introduce hierarchical lines

[DeteesWuber]

Problem statement:

The newly introduced separator lines between posts help to separate the content. However, the hierarchical level of replies (reply, reply to reply, reply to reply to reply) is still very difficult to see visually. So far, there is only a slight indentation when the screen is not split.

Proposed solution:

Visual indicators (perhaps lines?) are urgently needed to help distinguish the hierarchical levels of the discussion more clearly. They should clearly indicate the references, i.e. which post must be read as a response to which contribution.

User role(s):

admin,instructor,student,ta