Refactors the CLI to create the `*codersdk.Client` in the handlers. This is groundwork for changing the `rootCmd.InitClient()` to use the new `ClientOption`s.
It also improves variable locality, scoping the Client to the handler. This makes misuse less likely and reduces the memory allocations to just the command being executed, rather than allocating a Client for every command regardless of whether it is executed.
* feat: added whomai cmd to coder cli
* refactor: update Coder CLI's whoami command to use client URL instead of deployment config
* feat(cli): add unit tests for the whoami command
* chore(docs): add coder command to fetch authenticated user info
* chore(doc): update help desc
Spike Curtis