Share state across app instances

[praseodym]

OIDC login states are stored in a simple map which is not shared across instances and lost after container restarts:

mand/connect.go

Line 17 in 1ec2b7d

var states = map[string]bool{}

This impedes Kubernetes deployment scaling beyond a single pod (for HA and rolling restarts) and does not behave well in serverless environments such as Google Cloud Run. A solution could be to store state in an encrypted cookie using e.g. gorilla/sessions or gin-contrib/sessions.