rusk: Add a transactions by called contract endpoint

[HDauven]

Summary

A third party has requested a feature to display transactions related to their specific contract on the blockchain explorer. To support this, we need to expose a GraphQL query that allows filtering transactions based on the following criteria:

• Transactions of type contract_call.
• Contract ID matching a specified value.

This feature will allow clients/SDKs to query for contract interactions.

Possible Solution Design or Implementation

Expose a GraphQL query with parameters for filtering transactions by contract ID. The query should also support pagination to handle large datasets.

Example query:

query GetContractTransactions($contractId: String!, $limit: Int, $offset: Int) {
  transactions(
    filter: {
      contractId: $contractId
    },
    pagination: {
      limit: $limit,
      offset: $offset
    }
  ) {
    hash
    blockHeight
    timestamp
    contractId
    payload
    ...
  }
}

The implementation should filter for transactions of type type "contract_call" and a matching contractId. It should create appropriate indexing for query performance. It should return transaction details such as hash, block height, timestamp, contract ID, and payload.