CPFP support (#395)

* CPFP support.

fixes #5
fixes #353
fixes #360

* Use effectiveFeePerVsize for mempool statistics.

* Renaming endpoint cpfp-info to just cpfp.

* Renaming decended to BestDescendant.

* Updating language file with new strings.

frontend/src/app/interfaces/electrs.interface.ts

@@ -11,6 +11,7 @@ export interface Transaction {
 
   // Custom properties
   firstSeen?: number;
+  effectiveFeePerVsize?: number;
 }
 
 export interface Recent {

frontend/src/app/interfaces/node-api.interface.ts

@@ -8,3 +8,20 @@ export interface OptimizedMempoolStats {
   mempool_byte_weight: number;
   vsizes: number[] | string[];
 }
+
+interface Ancestor {
+  txid: string;
+  weight: number;
+  fee: number;
+}
+
+interface BestDescendant {
+  txid: string;
+  weight: number;
+  fee: number;
+}
+
+export interface CpfpInfo {
+  ancestors: Ancestor[];
+  bestDescendant: BestDescendant | null;
+}