NFT API: Added royalty related endpoints

[Sep 6, 2023]

1. For the existing endpoint Get metrics by collection, we added the following parameters in the response field: royalty_income, royalty_payers_num, average_royalty_income_per_sale, average_royalty_fee_rate_per_sale, theoretical_maximum_royalty_income, outstanding_royalty_income.
2. For the existing endpoint Get metrics by address, we added the following parameters in the response field: total_royalty_expense, theoretical_maximum_royalty_expense, outstanding_royalty_expense.
3. For the existing endpoint Get metrics by NFT, we added the following parameters in the response field: royalty_income, theoretical_maximum_royalty_income, outstanding_royalty_income.
4. For the existing endpoint Get holders by contract, we added the royalty_expense parameters in the response field. You can retrieve the total royalty expense of a wallet address now.
5. Added new endpoint Get royalty chart by contract, you can retrieve the daily royalty income of a collection now.
6. Added new endpoint Get marketplace royalty distribution by contract, you can retrieve the royalty income of different marketplaces for a collection now.
7. Added new endpoint Get royalty expenses by address, you can retrieve the royalty expenses on different collections for a wallet address now.