Decide on a packet format #3
Description
Since we want to be language independent and want a defined way to handle the packets, we need to decide on a packet format. Since we use CBOR in the GraphQL API it would make sense to use CDDL for this. However, we have to replace serde_cbor too (see #7 on minkan-chat/server). Would be perfect if ciborium would implement a CDDL generator from the rust structs 😄