Add config.MEMPOOOL.MAX_BLOCKS_BULK_QUERY parameter (default to 0, API disable)

backend/src/__tests__/config.test.ts

@@ -41,6 +41,7 @@ describe('Mempool Backend Config', () => {
         ADVANCED_GBT_AUDIT: false,
         ADVANCED_GBT_MEMPOOL: false,
         CPFP_INDEXING: false,
+        MAX_BLOCKS_BULK_QUERY: 0,
       });
 
       expect(config.ELECTRUM).toStrictEqual({ HOST: '127.0.0.1', PORT: 3306, TLS_ENABLED: true });