Netcore: Introduce BackofficeSecurityAccessor (#8871)

* Introduced IWebSecurityAccessor

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Fixed tests

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Renamed WebSecurity to BackofficeSecurity and all related names

* Fixes typos

Co-authored-by: Elitsa Marinovska <elm@umbraco.dk>

src/Umbraco.Tests.Integration/TestServerTest/UmbracoTestServerTestBase.cs

@@ -90,6 +90,7 @@ namespace Umbraco.Tests.Integration.TestServerTest
         {
             var url = LinkGenerator.GetUmbracoApiService<T>(methodSelector);
 
+            var backofficeSecurityFactory = GetRequiredService<IBackofficeSecurityFactory>();
             var umbracoContextFactory = GetRequiredService<IUmbracoContextFactory>();
             var httpContextAccessor = GetRequiredService<IHttpContextAccessor>();
 
@@ -104,6 +105,7 @@ namespace Umbraco.Tests.Integration.TestServerTest
                 }
             };
 
+            backofficeSecurityFactory.EnsureBackofficeSecurity();
             umbracoContextFactory.EnsureUmbracoContext();
 
             return url;