[enhancement] Handle CBOR-based protocols in a consistent way

I am interested in defining some CBOR-based protocols in scapy to take advantage of the good visualization and consistent user-facing interface provided by scapy.

The nice thing about CBOR is that it is composeable, with a sequence of items simply being the concatenation of the encoded forms of those items. But many CBOR-based protocols use array- and map-enveloping of fields as packets, which would need to be dealt with at the scapy integration layer.

I had created some basic field and packet subclasses to do this kind of thing in a scapy_cbor module but this breaks the scapy model of the encoded form being raw bytes (in the case of those classes the encoded form is a Python value which is then cbor2 encoded outside of scapy). I would like to massage this module into a more scapy-friendly one and submit this as a contrib module eventually.

Start by reading the linked scapy_cbor module and reviewing Scapy's conventions for contrib modules. Determine how CBOR array and map envelopes can fit Scapy's raw-byte packet model while supporting consistent field and packet behavior; done means a scapy-friendly contrib module suitable for the proposed CBOR-based protocols.