Make it easier to pick up the created JWT from the shell/tool calling qs-jwt

[mountaindude]

Let's say qs-jwt is called in a CI pipeline or from another system/tool.
It's currently more difficult than it should be to parse out the created JWT and use it in that calling tool.

Ideas:

1. Optionally store the created JWT in a file on disk. Make the file name configurable via an option.
2. Make the console output easier to parse when debug level is info or more verbose.
3. When debug level is error or warn the JWT could be sent to console as the only output from qs-jwt.

The above is applicable for both QS Cloud and QSEoW JWTs.