Add a tree list for navigation to apps and envs in the sidebar

[rohan-chaturvedi]

Is your feature request related to a problem?

Navigating to an app and environment requires several clicks.

Describe the solution you'd like

Add a tree list of apps and envs in the sidebar that the user has access to. Under the "Apps" item:

Apps
  |
  |--App 1
  |  |
  |  |-- Dev
  |  |-- Staging
  |
  |--App 2
  |  |-- Dev
  |
  |--App 3
  |  |
  |  |-- Dev
  |  |-- Staging
  |  |-- Production

• The list should be collapsible
• The current active App and Env should be highlighted
• Handle overflows, large number of apps etc