Update layout of UpdateView with links

[zeebok]

This addresses #106 and includes similar links as the welcome view.

[jeremypw]

@zeebok There seems to have been a lot of changes to Onboarding since this was started - is it still needed? If so, it would be helpful to post "Before" and "After" screenshots.

[zeebok]

@jeremypw Through all of the updates, the page that is affected hasn't changed so I think this PR is still relevant.
Before:

After:

[jeremypw]

Hmm thats odd 🤔 After installing master from source and running gsettings reset io.elementary.onboarding viewed; io.elementary.onboarding I got a different view with more pages. The page shown below had similar text on one link was the same. However after rebooting and logging in again I do get the three page view so it seems I was getting confused between the post-install and the post-update views. Sorry for the confusion. Maybe the README.md needs to clarify this.

[zeebok]

I do wonder if I should add the Community Support link to the What's New page as well. @cassidyjames what do you think?

[ahoneybun]

I feel like 3 items is pretty nice and even when it comes to sizing though if we need/want to add more 5 would be the next nice number.