Reduced nesting in the thread view

The proposal is to consider having less nesting in the thread view (while retaining the tree-like structure) for easier readability, optimized for the most common scenario where a long chain of replies gets flatten out (similarly to the twitter thread view).

The logic is roughly the following:

• The first reply (to any post) is displayed under its parent post (not nested).
• The second and Nths replies are nested / branched out (except for root replies).

(At the root level, the top level replies are visually separated from each other by not having the visual line connecting them together)

Example (each post has only one reply)

Before:

After: