Updating mempool logo and adding new mempool space logo. New frontend config OFFICIAL_MEMPOOL_SPACE to enable the latter.

fixes #336

frontend/src/app/components/master-page/master-page.component.html

@@ -3,7 +3,7 @@
   <nav class="navbar navbar-expand-md navbar-dark bg-dark">
   <a class="navbar-brand" [routerLink]="['/' | relativeUrl]" style="position: relative;">
     <ng-container *ngIf="{ val: connectionState$ | async } as connectionState">
-      <img src="./resources/mempool-logo.png" height="35" width="140" class="logo" [ngStyle]="{'opacity': connectionState.val === 2 ? 1 : 0.5 }">
+      <img [src]="officialMempoolSpace ? './resources/mempool-space-logo.png' : './resources/mempool-logo.png'" height="35" width="140" class="logo" [ngStyle]="{'opacity': connectionState.val === 2 ? 1 : 0.5 }">
       <div class="connection-badge">
         <div class="badge badge-warning" *ngIf="connectionState.val === 0" i18n="master-page.offline">Offline</div>
         <div class="badge badge-warning" *ngIf="connectionState.val === 1" i18n="master-page.reconnecting">Reconnecting...</div>

frontend/src/app/components/master-page/master-page.component.ts

@@ -13,6 +13,7 @@ export class MasterPageComponent implements OnInit {
   connectionState$: Observable<number>;
   navCollapsed = false;
   isMobile = window.innerWidth <= 767.98;
+  officialMempoolSpace = this.stateService.env.OFFICIAL_MEMPOOL_SPACE;
 
   constructor(
     private stateService: StateService,