Move user properties (like session keys) to their own table

model/user_props.go

@@ -0,0 +1,9 @@
+package model
+
+// UserPropsRepository is meant to be scoped for the user, that can be obtained from request.UserFrom(r.Context())
+type UserPropsRepository interface {
+	Put(key string, value string) error
+	Get(key string) (string, error)
+	Delete(key string) error
+	DefaultGet(key string, defaultValue string) (string, error)
+}