Add options for ephemeral mode CLI switcher prompt

[discdiver]

Describe the current behavior

The only option now is to switch to a different profile that has a PREFECT_API_URL set to a server.

$ prefect server start
Your current profile doesn't have 
`PREFECT_API_URL` set to the address of 
the server that's running. Some of your 
other profiles do.
? Which profile would you like to switch…
> default                                
  local                                  
  postgres   

Describe the proposed behavior

Would be nice to be able to create a new profile, exit, use ephemeral mode, or maybe copy an API URL to the currently active profile - for users who don't want to switch to one of the existing profiles.

Example Use

No response

Additional context

No response