Remove static Users auth, use shared QualityMapper for historian, simplify LDAP permission checks

- Remove ConfigUserAuthenticationProvider and Users property — LDAP is the only auth mechanism
- Fix historian quality mapping to use existing QualityMapper (OPC DA quality bytes, not custom mapping)
- Add AppRoles constants, unify HasWritePermission/HasAlarmAckPermission into shared HasRole helper
- Hoist write permission check out of per-item loop, eliminate redundant _ldapRolesEnabled field
- Update docs (Configuration.md, Security.md, OpcUaServer.md, HistoricalDataAccess.md)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.LmxOpcUa.IntegrationTests/SampleIntegrationTest.cs

@@ -1,20 +0,0 @@
-using Shouldly;
-using Xunit;
-
-namespace ZB.MOM.WW.LmxOpcUa.IntegrationTests
-{
-    /// <summary>
-    /// Placeholder integration test that keeps the integration test project wired into the solution.
-    /// </summary>
-    public class SampleIntegrationTest
-    {
-        /// <summary>
-        /// Confirms that the integration test assembly is executing.
-        /// </summary>
-        [Fact]
-        public void Placeholder_ShouldPass()
-        {
-            true.ShouldBeTrue();
-        }
-    }
-}