Follow-up of art #30375

The idea is to have a business-oriented (backlog, sprints…) approach to the sidebar rather than tools (trackers, agile dashboard…). This will result in:

• Improving the discoverability of a project, especially for novice users, as their business data will be "put forward" rather than "hidden" behind confusing tool names ("why do I need to click on Trackers to view my User stories? I don't even know what is a tracker")
• Easing access to current resources. Rather than constantly having to browse my workspace by tool then the resource (or tool > parent resource > ... > resource), the resources "pinned" in the sidebar are accessible with one click
• Giving the ability to quickly create resource from every page of the workspace

Stage 2 break down

Quick breakdown, to be refined:

• Inclusion of "floating buttons"
  • Search
  • New project
  • User menu
  • Invite a colleague
  • Help
  • Access to platform administration
• User sidebar
  • Shortcuts
  • My workspaces
• In-place sidebar customization