response caching for 24 hours

src/Icons/Controllers/IconsController.cs

@@ -27,6 +27,7 @@ namespace Bit.Icons.Controllers
         }
 
         [HttpGet("")]
+        [ResponseCache(Duration = 86400 /*24 hours*/, VaryByQueryKeys = new string[] { "url" })]
         public async Task<IActionResult> Get([FromQuery]string url)
         {
             if(string.IsNullOrWhiteSpace(url))

src/Icons/Startup.cs

@@ -31,6 +31,7 @@ namespace Bit.Icons
             {
                 options.SizeLimit = iconsSettings.CacheSizeLimit;
             });
+            services.AddResponseCaching();
 
             // Services
             services.AddSingleton<IDomainMappingService, DomainMappingService>();
@@ -46,6 +47,7 @@ namespace Bit.Icons
                 app.UseDeveloperExceptionPage();
             }
 
+            app.UseResponseCaching();
             app.UseMvc();
         }
     }