JSON-RPC: Additional methods for jamulusserver/*

[Rob-NY]

Short description of changes

NOTE THIS PR IS DEPENDENT ON #2918 (hence the compile failures -- I can submit both together here if that works better. Not sure how to note this dependency in github)

Added additional RPC methods for notification of connection, disconnection, and chats. Added the ability to send both broadcast chats to all connected clients, or targeted chats to a single connected client.

jamulusserver/clientConnect - a push notification on new client connect containing all info ("all info" is name, ip, instrument code, instrument name, skill code, skill name, country code, country name, city)
jamulusserver/clientDisconnect - a push notification on client disconnect containing channel, name, ip.
jamulusserver/clientInfoChanged - a push notification when a client changes any of their profile information.
jamulusserver/chatReceived - a push notification when a chat is received by the server including channel, name, ip, timestamp, and message.
jamulusserver/sendBroadcastChat - method to broadcast a server-level message to all connected clients.
jamulusserver/sendChat - method to send a chat to any individual connected channel based upon IP address.
Modified RPC methods:

CHANGELOG: Additional RPC methods for connection notification and chat processing.

Context: Fixes an issue?

Issue #2495 and discussion in #2890

Does this change need documentation? What needs to be documented and how?

Yes, RPC documentation updates are included in this PR.

Status of this Pull Request

What is missing until this pull request can be merged?

Linux tested/compiled only.

Checklist

• I've verified that this Pull Request follows the general code principles
• I tested my code and it does what I want
• My code follows the style guide
• I waited some time after this Pull Request was opened and all GitHub checks completed without errors.
• I've filled all the content above

[Rob-NY]

Removing this pull as it has diverged too far from its dependency #2918 which is also still pending.

[ann0see]

@Rob-NY As the other PR was finally merged, so you think your other work can also get a new PR?