Add `environment` drop down to pod logs screen
In preparation for showing logs on the Operations tab, we will need to allow users to choose the a particular environment. We should expose an option to allow you to select the environment you would like to view, but default to production on initial load, if it exists.
- We should consider the implementation of how this is/was done for Metrics, since it shares the same need: https://gitlab.com/gitlab-org/gitlab-ce/issues/45738
Original Design
There is an "Environment" dropdown after the "Container" dropdown.
Updated Design
- Introduce an environment dropdown
- Change the order of the dropdowns to reflect the underlying data structure (Environment > Pod > Container)
- Introduce labels above both the new and the existing dropdown to clarify what the dropdowns are
