Add optional Redis backend for load-balanced multi-instance Interactsh deployments

[realgam3]

Please describe your feature request:

Add optional Redis support alongside LevelDB so Interactsh can run multiple server containers behind a load balancer with shared state.

Describe the use case of this feature:

•	Enable horizontal scaling and high availability (no single-node bottleneck).
•	Share tokens, interaction events, and client/session metadata across instances.
•	Allow autoscaling in containerized environments without sticky sessions.
•	Keep LevelDB as the default; enable Redis via config (e.g., REDIS_URL, key prefix, TTLs).

[realgam3]

I can create the PR myself, just want to make sure you are on board...

[dogancanbakir]

@realgam3 Please, go for it!

[realgam3]

@realgam3 Please, go for it!

Thank you :)

For load-balancer support, I may extend -ip with DNS monitoring so addresses are resolved from DNS to keep it available