Add an option to list CAs

[ju916]

Request for feature: Add "--list" to display all active CA certificates.

This is easy to implement and allows to check, if your add operation was sucessfull. It would save people from having to face certutil itself ;-)

You just need to filter out the intermediate certificates that are saved in cert8.db also.

[ju916]

I did a simple implementation of a show-certs.cmd Use it as you see fit. show-certs.txt