Adding optional Blockstream esplora backend support.

backend/src/api/bitcoin/bitcoin-api-abstract-factory.ts

@@ -0,0 +1,10 @@
+import { IMempoolInfo, ITransaction, IBlock } from '../../interfaces';
+
+export interface AbstractBitcoinApi {
+  getMempoolInfo(): Promise<IMempoolInfo>;
+  getRawMempool(): Promise<ITransaction['txid'][]>;
+  getRawTransaction(txId: string): Promise<ITransaction>;
+  getBlockCount(): Promise<number>;
+  getBlock(hash: string): Promise<IBlock>;
+  getBlockHash(height: number): Promise<string>;
+}