Add masking. Add auth check

[alexespencer]

This change:

• masks password output when running krakenw auth --list by default
• adds a --no-mask switch to display the plain text password
• performs a credential check for jfrog.io and github by default, unless --no-check is provided. Most users are tripping up here and having credential check automatically performed (vs requesting it) will help
• displays curl commands for users to run themselves if they want to, requested via --verbose
• displays common warnings based upon the response received from JFrog (like using an API token vs an identity token)

Users can edit ~/krakenw/config.toml if they would like a different URL to be used for either jfrog or github:

[auth."helsing.jfrog.io"]
username = "alex.spencer@helsing.ai"
auth_check_url_suffix = "artifactory/api/pypi/python-all/simple/flask/"

For future changes, we'll need to extend the auth abilities, and may want to consider refactoring this so it's easier to maintain