move identityserver libs into core

src/Core/IdentityServer/AllowAllCorsPolicyService.cs

@@ -0,0 +1,13 @@
+using IdentityServer4.Services;
+using System.Threading.Tasks;
+
+namespace Bit.Core.IdentityServer
+{
+    public class AllowAllCorsPolicyService : ICorsPolicyService
+    {
+        public Task<bool> IsOriginAllowedAsync(string origin)
+        {
+            return Task.FromResult(true);
+        }
+    }
+}