Implements search functionality and prepares for upcoming paging in v0.3.

API/Helpers/UserParams.cs

@@ -2,6 +2,14 @@
 {
     public class UserParams
     {
-        
+        private const int MaxPageSize = 50;
+        public int PageNumber { get; set; } = 1;
+        private int _pageSize = 10;
+
+        public int PageSize
+        {
+            get => _pageSize;
+            set => _pageSize = (value > MaxPageSize) ? MaxPageSize : value;
+        }
     }
 }