Refactor test package and some field types

Fairly big test refactor and changing some of the fields from pointers

test/invalid-config-missing-alerts.hcl

@@ -0,0 +1,7 @@
+check_interval = "1s"
+
+monitor "Command" {
+    command = ["echo", "$PATH"]
+    alert_down = [ "alert_down", "log_shell", "log_command" ]
+    alert_every = 0
+}