Add `--verbose` flag to login

[EthanHeilman]

We have a --print-id-token in login ("Set this flag to print out the contents of the id_token. Useful for inspecting claims") #349 adds the ability to inspect and print ssh certs.

Now that we have #349 we should modify this so that

• combine code for --print-id-token and --print-ssh-key
• add --print-ssh-key
• Ensure that the formatting in --print-ssh-key and inspect matches the formatting of --print-id-token
• Add -v/--verbose flag to opkssh login that turns on --print-ssh-key