Implement NATS 2.0 Decentralized Security

[ccorley]

Implement NATS authorization via NATS 2.0 decentralized security and test across multiple LFH instances, each with configured NATS accounts and a new NATS account server.
https://itnext.io/secure-pub-sub-with-nats-fcda983d0612

As a part of this issue:

• Create a new NATS account server image with the nsc tool installed, in the /images repo.
• Modify LFH yml files to deploy a NATS account server based on the new image.
• Configure creation of core LFH operator and admin accounts in the NATS account server file system via nsc.
• Evaluate the use of exports to allow an admin on one LFH instance to see events from an admin on another LFH instance.
• Configure JetStream to use JWTs served from the NATS account server.
• Test across multiple LFH instances to ensure that events from the admin on one LFH instance can be received by the admin on another LFH instance.