Allow global handle persistence across servers

[ldilley]

Feature Summary

Dr.Funk from Discord inquired about how global handles work upon connecting to different SEGS servers. It was explained that the ID is currently local to each server instance given the decentralized nature of the software. This question and subsequent answer gave rise to the idea of allowing global handles to be persistent across a multitude of servers if they opt in.

Is your feature request related to a problem?

N/A

Proposed Implementation

Add a boolean configurable in settings.cfg to enable shared global handles (off by default.) Perhaps this could be done with SLAV and the list of global handles be maintained with the centralized server list.

Alternatives and Additional Remarks

Bonus points: Optionally integrate with Discord-ified (or IRC) global chat (#290.)

Screenshots, Diagrams or Attachments (if applicable)

N/A