Name log fields, metrics and the Core Rule Set package for what they are (closes #192)

Log field, metric, action and event names now say what they count
and, for timings, the unit. Package internal/waf is internal/coreruleset.

Model: opus-5-5

internal/lookup/lookup_test.go

@@ -846,7 +846,7 @@ func wantAsked(t *testing.T, geojs *standIn, i int, want ...string) {
 func wantUnanswered(t *testing.T, m *metrics.Metrics, want float64) {
 	t.Helper()
 
-	got := testutil.ToFloat64(m.GeoJSUnanswered)
+	got := testutil.ToFloat64(m.RequestsWithoutGeoJSAnswer)
 	if got != want {
 		t.Errorf("%v requests went without an answer, want %v", got, want)
 	}