Reworked encryption to use less heap allocated buffers for secrets.

Also some work on plugin system.

IdentityShroud.PluginSupport/IPlugin.cs

@@ -0,0 +1,9 @@
+namespace IdentityShroud.PluginSupport;
+
+/// <summary>
+/// Any class that should be discovered when loading a dll should implement IPlugin
+/// </summary>
+public interface IPlugin
+{
+    
+}

IdentityShroud.PluginSupport/IdentityShroud.PluginSupport.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>