Add NFT query api: ListNftApprove

[elonkusk]

Support ListNftApprove:

• Because some account don't know that it's delegated to approve some of NFT token, so we should support this listing api

• Input:

        message NftTokenApproveQuery{
          bytes owner_address = 1;
          int32 page_size = 2;
          int32 page_index = 3;
        }
  

• Output:

        message NftTokenApproveResult{
          bytes owner_address = 1;
          int32 page_size = 2;
          int32 page_index = 3;
          int64 total = 4;
          repeated NftToken tokens= 5;
        }
  

• How to implement ?

  • In account-token relation, add indexing field for token approve list:

        message NftAccountTokenRelation{
                        bytes approve_head = 7; //point to head of tokenapprove
                        bytes approve_tail = 8;//point to tail of tokenapprove
                        int64 approve_total = 9; //total token
                    }
    

  • Add new account-tokenapprove indexing store with this structure that link to real nft token:

          message NftTokenApproveRelation{
              bytes owner_address = 1;
              bytes token_id = 3;
              bytes next = 8;
              bytes prev = 9;
        }
    

  • when approve/disapprove: modify these structure

  • when listing: load, paging data