Need some documentation to explain workspace, environment and group

[vinayada1]

What content needs to be created or modified?

Explain the concept of Radius workspace, environment and group and how they are related to each other. Currently, the user is exposed to these concepts via the rad CLI commands. It would be good to have some explanation why each of these means and is needed for.

Describe the solution you'd like

Documentation explaining these concepts

Where should the new material be placed?

Under concepts or FAQ

The associated pull request from the Radius code repo, if applicable

Additional context

AB#10070

[nicolejms]

Discord discussion where customer confused as to terminology.

[Reshrahim]

Another community user needing some guidance around workspace, resource groups, environments and applications - https://discord.com/channels/1113519723347456110/1113519723930468455/1181928149609615370