feat: teams/organizations to group multiple projects

[marcklingen]

We will need to add a a team/organization ("team") level to group multiple projects. These all relate to permissions. Currently permissions are managed on project-level. With switch to team, permissions could in addition be also managed on team level

Blocked features / use cases

• Copy items between projects (e.g. dev/prod with different people having access to these projects)
• Create "internal" project to store traces of langfuse features used within organization, e.g. playground
• Manage permissions for larger teams across multiple projects, potentially via API
• API keys that have access to multiple projects
  • create new projects via api
  • Same application should trace to different projects - e.g. multi-tenant application with customers having access to langfuse instances
• self-host: create default team with default api keys. this team can then create projects programmatically
• Cloud: simplify billing with multiple projects on the same billing account