bruig: style issues on feed/post screens

[bochinchero]

Seen on 0.2.2 android and Windows.

A few minor ui issues:

1. Timestamps are in the yyyy-MM-dd'T'HH:mm:ss.SSS format which makes it quite a long string to have on every comment, particularly in smaller screens - see the image below:

The format used in the main Feed screen (##w, ##d, ##h) with a tooltip showing the timestamp down to seconds (like in the chats) could be cleaner?

2. On smaller screens/mobile, the margin/padding on the left side takes up a big chunk of the space - particularly when reading child comments multiple level down, see the screenshot below.

3. Really minor, but the location of the scroll bar in the main Feed screen is different than the post/comment screen and the chats