feat (security): Support encrypted keychains for credential storage

[timoguin]

Although the CLI already supports setting the GOLDAP_PASSWORD environment variable for configuring authentication for simple LDAP binds, we should add support for encrypted credential stores. There are libraries that can make this fairly straight-forward, so the bulk of this issue is going to be UX design.

Considerations

• Users may want to store multiple credentials
• Users may want to map named credentials
• Users may want to include the bind-dn and/or ldap-uri (along with the password as a named bundle)
• Users need to be able to update stored credentials

Ideas

• Add some kind of auth command for managing credentials
• Allow named credential sets that can be referenced in subcommands
• Provide a mutable default alias and an interface to manage it
• Use a host-based config format that allows

References

• 99designs/keyring library