create separate service for short term tx & block caching

frontend/src/app/app.module.ts

@@ -6,6 +6,7 @@ import { AppRoutingModule } from './app-routing.module';
 import { AppComponent } from './components/app/app.component';
 import { ElectrsApiService } from './services/electrs-api.service';
 import { StateService } from './services/state.service';
+import { CacheService } from './services/cache.service';
 import { EnterpriseService } from './services/enterprise.service';
 import { WebsocketService } from './services/websocket.service';
 import { AudioService } from './services/audio.service';
@@ -23,6 +24,7 @@ import { AppPreloadingStrategy } from './app.preloading-strategy';
 const providers = [
   ElectrsApiService,
   StateService,
+  CacheService,
   WebsocketService,
   AudioService,
   SeoService,