Use ring crate to generate StatHashes when saving stateid/statehash

Cargo.toml

@@ -33,7 +33,7 @@ image = { version = "0.23.4", default-features = false, features = ["jpeg", "png
 base64 = "0.12.3" # Used to encode server public key
 # state-res = { path = "../../state-res" }
 state-res = { git = "https://github.com/ruma/state-res", version = "0.1.0" }
-
+ring = "0.16.15"
 
 [features]
 default = ["conduit_bin"]