Added fee distribution Pie Chart to the block inspector.

frontend/src/app/fee-distribution-graph/fee-distribution-graph.component.html

@@ -0,0 +1,30 @@
+<div style="height: 400px;" *ngIf="mempoolVsizeFeesData; else loadingFees">
+  <form [formGroup]="radioGroupForm" style="position: absolute;">
+    <div class="btn-group btn-group-toggle" ngbRadioGroup name="radioBasic" formControlName="model">
+      <label ngbButtonLabel class="btn-primary btn-sm">
+        <input ngbButton type="radio" value="line"> Line
+      </label>
+      <label ngbButtonLabel class="btn-primary btn-sm">
+        <input ngbButton type="radio" value="pie"> Pie
+      </label>
+    </div>
+  </form>
+  <app-chartist
+    *ngIf="radioGroupForm.get('model')?.value === 'pie'"
+    [data]="mempoolVsizeFeesPieData"
+    [type]="'Pie'"
+    [options]="mempoolVsizeFeesPieOptions">
+  </app-chartist>
+  <app-chartist
+    *ngIf="radioGroupForm.get('model')?.value === 'line'"
+    [data]="mempoolVsizeFeesData"
+    [type]="'Bar'"
+    [options]="mempoolVsizeFeesOptions">
+  </app-chartist>
+</div>
+
+<ng-template #loadingFees>
+  <div class="text-center">
+    <div class="spinner-border text-light"></div>
+  </div>
+</ng-template>