Enhance ExternalSloChecker logging

theodolite/src/main/kotlin/theodolite/evaluation/ExternalSloChecker.kt

@@ -40,7 +40,7 @@ class ExternalSloChecker(
             val result = post(externalSlopeURL, data = data, timeout = TIMEOUT)
             if (result.statusCode != 200) {
                 counter++
-                logger.error { "Could not reach external SLO checker." }
+                logger.error { "Could not reach external SLO checker at $externalSlopeURL." }
             } else {
                 val booleanResult = result.text.toBoolean()
                 logger.info { "SLO checker result is: $booleanResult." }
@@ -48,6 +48,6 @@ class ExternalSloChecker(
             }
         }
 
-        throw ConnectException("Could not reach external SLO checker")
+        throw ConnectException("Could not reach external SLO checker at $externalSlopeURL.")
     }
 }