Implement a new commit box for narrow viewports in Repository views

Context

In previous issue, we had missed some technical hurdles that required us to build new vue components to address the functionality requested.

We've decided to spin off this part of the work to a new issue to track that effort separately.

Work has already started in 17.6

Narrow viewports

In narrow viewports, the History button currently goes full width but the change in this issue makes the change that the History is combined with the commit information.

At narrow viewports instead of the button we will display a gray information box that starts the size of the current button but with progressive disclosure we can show more information.

Things to display:

• Avatar: Displayed to show the who in the latest change
  • Not displaying name as there could be long names and/or multiple author/commiters that could affect the layout. This could be revealed in the expanded state.
• Time: Displayed to show the when was the latest change
• Commit: Reference to the latest change, clicks on it goes to the commit detail view
• ellipsis: View commit details inline
  • This is a nice to have as there is no existing issue asking for this information but since we already do this for the wider viewports it feels natural to include this behaviour in for narrow viewports too. Also having it expandable would reveal the name of the authors.
• History: Links to the commit list (current behaviour)

Current	Proposal - Default	Proposal - Expanded