Updated ad placeholder graphics, update Modrinth App sidebar to mockup designs (#4584)

* Update ad placeholders to new green graphic

* Remove rounded corners from app ad frame

* Improve web ad placeholder styling

* Revamp app sidebar to match mockups more closely, greatly improve friends UX, fix up context menus and typify shit

* only show overflow on hover

* lint

* intl:extract

* clean up the inline code in FriendsSection

packages/assets/icons/user-cog.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-user-cog-icon lucide-user-cog"><path d="M10 15H6a4 4 0 0 0-4 4v2"/><path d="m14.305 16.53.923-.382"/><path d="m15.228 13.852-.923-.383"/><path d="m16.852 12.228-.383-.923"/><path d="m16.852 17.772-.383.924"/><path d="m19.148 12.228.383-.923"/><path d="m19.53 18.696-.382-.924"/><path d="m20.772 13.852.924-.383"/><path d="m20.772 16.148.924.383"/><circle cx="18" cy="15" r="3"/><circle cx="9" cy="7" r="4"/></svg>