feat: add redis configuration options

FastAPIs redis-plugin picks them up automatically

.env

@@ -1,6 +1,13 @@
 secret=please_please_update_me_please
 algorithm=HS256
 
+# Redis - uncomment if Redis runs with non standard values (i.e. in Docker etc)
+# redis_host=127.0.0.1
+# redis_port=6379
+# redis_db=0
+# leave commented if no password is used
+# redis_password=my_password
+
 # mainnet or testnet
 network=testnet
 bitcoind_ip_mainnet=192.168.1.18