EPIC: Creation of the `polykey auth` command subdomain

[tegefaulkes]

Specification

This Issue is a epic that tracks the wider implementation of the authentication (auth) subcommand. This subcommand generally wraps any authentication based action in PK-CLI. This will include the login, passkey and any other command we need to support.

Here is a non-exaustive list of subcommands to eventually be implemented.

• login
• passkey

Additional context

Tasks

1. Create the auth subcommand in Polykey-CLI.
2. Create the auth login command to support logging into PKE.
3. Create the auth passkey command to support logging in via a passkey login flow.

[linear]

ENG-631