Investigate alternative discovery mechanisms

[markafoltz]

Follow-up from Berlin F2F - See slide 43 of the slide deck

This is a placeholder to investigate alternative discovery mechanisms. Currently we have specified SSDP as the non-mandatory alternative to mDNS for the V1 Open Screen protocol. We can look at additional alternatives that may include (but not be limited to):

• A new, simpler multicast protocol that just broadcasts CBOR records.
• Bluetooth
• Internet DNS or cloud based registries
• QR codes
• NFC

Some may be out of scope per charter. We will need to scope or revise the charter appropriately; when that is done, we can open sub-issues for further investigation.