feature: Save application metrics to db for alerting (#7828)

* feature: save application metrics to db for alerting
However, alerting will not work because ResolveGlues() is broken.
Can add workaround after state_translations alerting is merged

Does not update all applications yet, not sure if that should be done here or in another PR.

Introduces two handy functions dbDeleteOrphans() and array_by_column().  Will replace those in other locations after this is merged or separate them out if this is not merged.

* remove accidental inclusions

* Add db schema

includes/common.php

@@ -1866,3 +1866,15 @@ function check_file_permissions($file, $mask)
 
     return ($perms & $mask) === $mask;
 }
+
+/**
+ * Index an array by a column
+ *
+ * @param array $array
+ * @param string|int $column
+ * @return array
+ */
+function array_by_column($array, $column)
+{
+    return array_combine(array_column($array, $column), $array);
+}