command for new workspace

Describe the problem you are trying to solve
use cargo new to make workspace for multi bins and libs

Describe the solution you'd like
option to cargo new to setup workspace Cargo.toml not just bin or lib. maybe relate to #9823

Notes

[ehuss]

Thanks for the suggestion! I think this is pretty much the same as #8365 (combined with #9823), so closing as a duplicate of that.