LaunchDarkly: establish master configuration document/tool

[severinbeauvais]

Ref: #15734

The purpose of such a document/tool is to:

• improve visibility of current configuration (per environment)
• track flag change history (and authorization?)
• serve as a backup in case recovery is needed
• identify obsolete flags
• identify flags that look obsolete but are needed to possibly turn off a feature (even though it's released) in the foreseeable future

Ideally this document/tool would be automatically synchronize/integrated with LaunchDarkly so that LD managers don't have to update both LD and a document.

[severinbeauvais]

Thor said:

We should be able to report out, and possible connect up 1Password. Would be worth a look, especially since we'll have a fair number of them during this build out.