Introduce an info bar to the Feature Flag detail view

Release notes

Problem to solve

There is a lot of different pieces of information that relate to a single feature flag. Unfortunately, this data is scattered throughout the UI and can make it difficult to quickly understand the status of a feature flag in flight.

Proposal

Add an "info bar" that contains a lot of information, including the feature flag ID, number of total strategies (number of active strategies), and list of environments.

Proposed design