Project dropdown

[brillout]

• Replace the current Project collapsible with a dropdown of all projects => user can select one or multiple projects
• Data shown on all pages are filtered: only data of the selected projects is shown (filter tickets data, overview data, recent sessions, ...)
• Move the dropdown all the way to top in the sidebar, right below "The Framework" text & logo.
• Visually separate the top section (logo + project dropdown) from the rest of the sidebar, so that it's clear that the selected projects apply to evertyhing — maybe also use some kind of extra visual clue to communicate it (we can brainstorm here)
• All the selected projects are shown on top of the dropdown
• The dropdown is a multi-select that shows a checkbox for each project
  • The dropdown also has a special value "All"
  • When clicking on a checkbox => add/remove project
  • When clicking outside the checkbox (on the project line anywhere outside the checkbox) => only select this project (remove all other projects)
  • Use tooltips to further clarify how to use (although it should be relatively clear even without tooltips)