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/discriminator/bans.go

@@ -106,7 +106,7 @@ func (rq *request) banForLimit(now time.Time, hit ratelimit.Hit, status int) {
 	case ratelimit.KindBytes:
 		rq.line.LimitHit = hit.Window + "_bytes" // as counts names the byte totals
 	case ratelimit.KindRefusals:
-		rq.line.LimitHit = requestlog.LimitHitErrorBurst
+		rq.line.LimitHit = requestlog.LimitHitMinuteRefusals
 	default:
 		rq.line.LimitHit = hit.Window
 	}