Token allow list feature. Bank module changes (#538)

## Describe your changes and provide context
This change is part of token allow list feature implementation for token
extensions.
Added functions to:
- persist denom allow list and query it
- check if `from` and `to` addresses are in allowlist on bank send and
multi-send

## Testing performed to validate your change
- unit testing
- functional testing (plugged modified code into sei-chain) and via
ERC-20 pointer contract

proto/cosmos/bank/v1beta1/bank.proto

@@ -94,3 +94,10 @@ message Metadata {
   // Since: cosmos-sdk 0.43
   string symbol = 6;
 }
+
+message AllowList {
+  option (gogoproto.equal) = true;
+
+  // Can be empty for no admin, or a valid sei address
+  repeated string addresses = 1 [ (gogoproto.moretags) = "yaml:\"addresses\"" ];
+}