Aggregator/Signer preload transactions when Cardano transactions certification is not activated

[jpraynaud]

Why

The signer and aggregator node import the Cardano transactions during the pre-loading phase, even if this type of data is not activated on the network. The expected behavior is to have the preloading triggered only when the aggregator has activated the Cardano transaction signed entity type.

What

Trigger the signer preloading of the Cardano transactions only if the aggregator advertises the CardanoTransactions in the signed entity types in its root route, and the aggregator preloading of the Cardano transactions only if the CardanoTransactions signed entity type is activated.

How

• Create a common trait CardanoTransactionsPreloaderActivationState with a async fn is_activated() -> StdResult<bool> function
• Use the CardanoTransactionsPreloaderActivationState in the aggregator to check if the preloading can be done before preloading
• Use the CardanoTransactionsPreloaderActivationState in the signer to check if the preloading can be done before preloading