Add avatar color support

The new web-vault v2023.1.0 supports a custom color for the avatar.
https://github.com/bitwarden/server/pull/2330

This PR adds this feature.

src/db/schemas/mysql/schema.rs

@@ -200,6 +200,7 @@ table! {
         client_kdf_type -> Integer,
         client_kdf_iter -> Integer,
         api_key -> Nullable<Text>,
+        avatar_color -> Nullable<Text>,
     }
 }