feat(cli): add --primary-config, --backup-config, --failover-retry-count to data connection commands

Thread backup data connection fields through management command messages,
ManagementActor handlers, SiteService, site-side SQLite storage, and
deployment/replication actors. The old --configuration CLI flag is kept
as a hidden alias for backwards compatibility.

tests/ScadaLink.TemplateEngine.Tests/Services/SiteServiceTests.cs

@@ -93,7 +93,7 @@ public class SiteServiceTests
         _repoMock.Setup(r => r.SaveChangesAsync(It.IsAny<CancellationToken>()))
             .ReturnsAsync(1);
 
-        var result = await _sut.CreateDataConnectionAsync(1, "OPC-Server1", "OpcUa", "{\"url\":\"opc.tcp://localhost\"}", "admin");
+        var result = await _sut.CreateDataConnectionAsync(1, "OPC-Server1", "OpcUa", "{\"url\":\"opc.tcp://localhost\"}", null, 3, "admin");
 
         Assert.True(result.IsSuccess);
         Assert.Equal("OPC-Server1", result.Value.Name);