Do not use anything else than strings and services / gateways in the cli package

[Jonas-Karl]

Description
We should try to write the cli in a way that it does not know anything about our core domain. It should only be able to create Strings and parse Strings via other more internal classes

Ready Criteria

• everyone understood the scope of this ticket
• effects in domain- / useCase- / external-layers are discussed
• atleast one person is assigned

Acceptance Criteria

• CLI does not use anything like Mailbox.Types, Labels, Emails, Addresses, Users and so on

Scope

• [ ]

Additional context
Add any other context or screenshots about the feature request here.