PLATFORM: Sidebar revamp and make it collapsable

Description

Figma: https://www.figma.com/design/Du3qt5NWbbnfMgtU5CQYCU/Keyshade-UI?node-id=5786-4009&t=2gr9umJw99acBmtL-0

• [ ] Make the sidebar collapsable
• [ ] Adopt to the new design

<!-- upstream-issue: keyshade-xyz/keyshade#1125 -->