refactor: Small improving of the cip36 parsing (#450)

* fix config fetching

* refactor

* add cddl validation

* fix cddl

catalyst-gateway/bin/src/cardano/cip36_registration/cip36_registration.cddl

@@ -1,17 +1,21 @@
 
-registration = {
+key_registration = {
   1 : [+delegation] / legacy_key_registration,
-  2 : stake_credential,
-  3 : payment_address,
-  4 : nonce,
-  ? 5 : voting_purpose .default 0
+  2 : $stake_credential,
+  3 : $payment_address,
+  4 : $nonce,
+  ? 5 : $voting_purpose .default 0
 }
 
-cip36_vote_pub_key /= bytes .size 32
-payment_address /= bytes
-nonce /= uint
-weight /= uint .size 4
-voting_purpose /= uint
-legacy_key_registration = cip36_vote_pub_key
-delegation = [cip36_vote_pub_key, weight]
-stake_credential /= staking_pub_key
+$cip36_vote_pub_key /= bytes .size 32
+$payment_address /= bytes
+$nonce /= uint
+$weight /= uint .size 4
+$voting_purpose /= uint
+legacy_key_registration = $cip36_vote_pub_key
+delegation = [$cip36_vote_pub_key, $weight]
+
+
+$stake_credential /= $staking_pub_key
+; A stake key credential, not tagged for backward compatibility
+$staking_pub_key /= bytes .size 32

catalyst-gateway/bin/src/cardano/cip36_registration/cip36_witness.cddl

@@ -1,5 +1,7 @@
 registration_witness = {
-  1 : stake_witness
+  1 : $stake_witness
 }
 
-stake_witness /= ed25519_signature
+$stake_witness /= $ed25519_signature
+; Witness for a stake key credential, not tagged for backward compatibility
+$ed25519_signature /= bytes .size 64