Fix #4936: add the cookie consent theme control.

Oqtane.Client/Themes/BlazorTheme/Themes/Default.razor

@@ -26,9 +26,11 @@
         <div class="container">
             <div class="row px-4">
                 <Pane Name="@PaneNames.Admin" />
+                <CookieConsent />
             </div>
         </div>
     </div>
+    
 </div>
 
 @code {

Oqtane.Client/Themes/Controls/Theme/CookieConsent.razor

@@ -0,0 +1,33 @@
+@namespace Oqtane.Themes.Controls
+@inherits ThemeControlBase
+@inject ICookieConsentService CookieConsentService
+@inject IJSRuntime JSRuntime
+@inject IStringLocalizer<CookieConsent> Localizer
+
+@if (showBanner)
+{
+    <form method="post" @formname="CookieConsentForm" @onsubmit="async () => await AcceptPolicy()" data-enhance>
+        <input type="hidden" name="@Constants.RequestVerificationToken" value="@SiteState.AntiForgeryToken" />
+        @((MarkupString)Convert.ToString(Localizer["ConsentBody"]))
+    </form>
+}
+@code {
+    private bool showBanner;
+
+    protected override async Task OnInitializedAsync()
+    {
+        showBanner = !(await CookieConsentService.CanTrackAsync());
+    }
+
+    private async Task AcceptPolicy()
+    {
+        var cookieString = await CookieConsentService.CreateConsentCookieAsync();
+        if (!string.IsNullOrEmpty(cookieString))
+        {
+            var interop = new Interop(JSRuntime);
+            await interop.SetCookieString(cookieString);
+
+            showBanner = false;
+        }
+    }
+}

Oqtane.Client/Themes/OqtaneTheme/Themes/Default.razor

@@ -107,6 +107,7 @@
         {
             <Pane Name="Footer" />
         }
+        <CookieConsent />
 	</div>
 </main>