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

EnvelopeGenerator.Web/Views/Home/EnvelopeLocked.cshtml

@@ -1,4 +1,7 @@
 @{
+    var nonce = _accessor.HttpContext?.Items["csp-nonce"] as string;
+}
+@{
     ViewData["Title"] = "Dokument geschützt";
     var userLanguage = ViewData["UserLanguage"] as string;
     var languages = ViewData["Languages"] as string[];
@@ -50,7 +53,7 @@
     </section>
 </div>
 <footer class="container" id="page-footer">&copy; SignFlow 2023-2024 <a href="https://digitaldata.works">Digital Data GmbH</a></footer>
-<script>
+<script nonce="@nonce">
     $(document).ready(function () {
         $('.select-flag').select2({
             templateResult: formatResult,