Quick Start tour feedback based updates and fixes. Part 2

Created by: erzhtor

Logos and text should be center-aligned on horizontal variant
Remove left padding/margin on list on the horizontal variant. Should not change current vertical behavior
Change:   ”Learn how to find and fix vulnerabilities faster” to   ”Find problem code in diffs”. Diff search is a major feature and we need to explicitly call it out to solicit clicks.   Also, it is unclear how the diff search relates to vulnerabilities
Hide vertical/horizontal scroll bars. This is not a pattern we use elsewhere in the application. Check on Chrome and Firefox
Completed tasks design updates