preserve filters while paginating (#405)

src/Web/Pages/Shared/_pagination.cshtml

@@ -1,5 +1,14 @@
 @model PaginationInfoViewModel
-
+@{
+    var prevRouteData = Context.Request.Query.ToDictionary(x => x.Key, x => x.Value.ToString());
+    if (prevRouteData.ContainsKey("pageId"))
+        prevRouteData.Remove("pageId");
+    prevRouteData.Add("pageId", (Model.ActualPage - 1).ToString());
+    var nextRouteData = Context.Request.Query.ToDictionary(x => x.Key, x => x.Value.ToString());
+    if (nextRouteData.ContainsKey("pageId"))
+        nextRouteData.Remove("pageId");
+    nextRouteData.Add("pageId", (Model.ActualPage + 1).ToString());
+}
 <div class="esh-pager">
     <div class="container-fluid">
         <article class="esh-pager-wrapper row">
@@ -7,7 +16,7 @@
                 <div class="col-md-2 col-xs-12">
                     <a class="esh-pager-item-left esh-pager-item--navigable esh-pager-item @Model.Previous"
                        id="Previous"
-					   asp-route-pageid="@(Model.ActualPage - 1)"
+                       asp-all-route-data="prevRouteData"
                        aria-label="Previous">
                         Previous
                     </a>
@@ -22,7 +31,7 @@
                 <div class="col-md-2 col-xs-12">
                     <a class="esh-pager-item-right esh-pager-item--navigable esh-pager-item @Model.Next"
                        id="Next"
-					   asp-route-pageid="@(Model.ActualPage + 1)"
+                       asp-all-route-data="nextRouteData"
                        aria-label="Next">
                         Next
                     </a>