Add button to open Home View from Graph

[justinrobots]

Add a button to the Commit Graph header that opens the GitLens Home View so users can easily jump between Home and the Graph.

• use the GitLens logo
• add a hover style similar to the existing "Open in GitHub button" (see example)
• add a tooltip on hover that says "Open GitLens Home View"
• open the GitLens Home View when clicked

Mockup:

Example of the "Open in GitHub button":

[nzaytsev]

@justinrobots - would it make sense to add a similar button to the home view to have ability to open the commit graph?

[eamodio]

@justinrobots do we really want this on the left side? Shouldn't it be on the right side, to the right of launchpad? I would also suggest we have a little more description for what Home is (like we do for the launchpad button)

@nzaytsev we do have a button on Home to go to the Graph

[eamodio]

@nzaytsev Please move this button to the right of the Launchpad item.