Added support for per site options and OpenID Connect

Oqtane.Server/Infrastructure/Options/SiteOptionsManager.cs

@@ -0,0 +1,35 @@
+using Microsoft.Extensions.Options;
+
+namespace Oqtane.Infrastructure
+{
+    public class SiteOptionsManager<TOptions> : IOptions<TOptions>, IOptionsSnapshot<TOptions> where TOptions : class, new()
+    {
+        private readonly IOptionsFactory<TOptions> _factory;
+        private readonly IOptionsMonitorCache<TOptions> _cache; // private cache
+
+        public SiteOptionsManager(IOptionsFactory<TOptions> factory, IOptionsMonitorCache<TOptions> cache)
+        {
+            _factory = factory;
+            _cache = cache;
+        }
+
+        public TOptions Value
+        {
+            get
+            {
+                return Get(Options.DefaultName);
+            }
+        }
+
+        public virtual TOptions Get(string name)
+        {
+            name = name ?? Options.DefaultName;
+            return _cache.GetOrAdd(name, () => _factory.Create(name));
+        }
+
+        public void Reset()
+        {
+            _cache.Clear();
+        }
+    }
+}