Splits database into a separate crate

gamenight-database/src/error.rs

@@ -0,0 +1,13 @@
+pub struct DatabaseError(pub String);
+
+impl From<diesel::result::Error> for DatabaseError {
+    fn from(value: diesel::result::Error) -> Self {
+        DatabaseError(value.to_string())
+    }
+}
+
+impl From<argon2::password_hash::Error> for DatabaseError {
+    fn from(value: argon2::password_hash::Error) -> Self {
+        DatabaseError(value.to_string())
+    }
+}