Blog post layout wastes too much space in the header

[vcoisne]

Moved from @dpordomingo comment at https://github.com/src-d/feature-idea/issues/135

Describe the problem
UX problem.
When the user clicks in a blog card (from Landing, or from any internal link), it goes to the post but the browser window is mostly occupied by a huge and useless header.

example

Describe the solution you'd like
Posts should be opened with the post title in the very top.

Alternatives
Ordered by personal preference:

• Post layout should use a small version of the header
  • it may be collapsed by default, with a button to open it,
  • or not having the huge mega header at all.
• Javascript to scroll to the title on post-load

[vcoisne]

@znegrin is it possible to remove the "sourced blog" and tags for the posts?