Make use of keycloak default configuration and add a config command that helps in saving configuration and token to auth configuration file

This is a follow up of swh-scanner!72 (closed)

• Add configuration file argument to auth command group
• Use keycloak default configuration and defaults method to load and merge configuration (env > params > user configuration file > default auth configuration > defaultvalues)
• Add swh auth config command which can generate a token by providing a username (password will be asked by a prompt), or verify a provided token. If the token is valid user can save the authentication configuration with token to authentication configuration file which default to auth.yml

Related to swh-scanner#4590