Add path per line output for db list

[ecooper]

Problem

fauna db list only outputs JSON. When running the command without the --database flag, it's pretty verbose without providing a ton of value.

Solution

If we update the output to be a path per line by default, we can simplify the output and shrink it down. --json can then output the JSON parsable version.

Because we sometimes use the account API and sometimes use FQL directly, we can only really output a shape that looks like:

{
  name: string;
  path?: string;
}

When path is unavailable, we'll output a warning message to stderr to let folks know the full path is not retrievable when using a secret.

Result

When using --database:

When using --secret:

Testing

Updated the tests for list to prove the new output formats.

[jrodewig]

Maybe not in scope here, but we may want to output a message if there are no databases in the current scope. Right now, it's just nothing — which makes sense — but I always wonder if I messed up the command.