Tracking: Zebra is a full participant in the Zcash Network

[mpguerra]

Once the work to validate NU5 and previous network upgrades is completed, we will work on ensuring that Zebra is a full participant in the Zcash Network. This work may include:

Required:

• Maintaining a mempool (Tracking: Mempool #2309)
• Inbound message handling (Tracking: inbound message handling. #889)
• Security issues (Tracking: Security Issues #2311)
  -- Severe impact on other nodes
  -- Severe impact on the local node

Optional:

• zebrad usability improvements (Tracking: zebrad Usability #2310)
• Paying back Tech Debt (Tracking: Tech Debt #2312)
• Documentation Updates (Tracking: Documentation #2313)

This work may be equivalent to the work we need to do before we put out a stable release and replaces the First stable / major version release 📦 milestone:

"After our first alpha (Sync and Validation) there are a few items / features we want to get done before we consider ourselves 'a well-behaved full node'. The items in this milestone also include the investments we need to make in conformance testing and release engineering/infra to get our software to users."

[mpguerra]

This feels obsolete now that we: a) are fully validating all consensus rules, b) are implementing a mempool, c) have plans for a stable release candidate.

Converting to an issue and closing.