This patch moves the revision list from the tab bar drop-down to a sidebar on wide screens and above the current revision on narrow screens. This way all revisions are visible at all times.

We also move and nest the revision reviews into that list so that one can see whether there's anything actionable at a glance.

Other tweaks:

• added comment counts to revisions and reviews
• displayed unresolved comment thread counts per review
• swapped icons for accepted/rejected and neutral reviews to avoid clashing with resolved/unresolved comment icons
• made label and assignee sections more compact with hover-triggered "+" buttons
• added author and status sections to the sidebar
• enabled patch state changes from the title bar
• made "Review revision" the primary action and "Checkout patch" secondary
• added "Draft" label to draft patches
• capitalized all badges for consistent UI text