feat: Add CSP configuration to use CSPMiddleware and CSP nonce to script tags in several cshtml script

EnvelopeGenerator.Web/Program.cs

@@ -16,6 +16,7 @@ using EnvelopeGenerator.Web.Models;
 using DigitalData.Core.DTO;
 using System.Text.Encodings.Web;
 using Ganss.Xss;
+using EnvelopeGenerator.Web;
 
 var logger = LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();
 logger.Info("Logging initialized!");
@@ -183,15 +184,12 @@ try
     }
 
     app.UseHttpsRedirection();
-    app.UseStaticFiles();
 
     var csp = config["Content-Security-Policy"];
     if(csp is not null)
-        app.Use(async (context, next) =>
-        {
-            context.Response.Headers.Add("Content-Security-Policy", csp);
-            await next();
-        });
+        app.UseCSPMiddleware(csp);
+
+    app.UseStaticFiles();
 
     app.UseCookiePolicy();