Request tags, with refusing and limits per tag (closes #175)

Each request gets sorted tags from the lookup, new address lists, the
reputation sources and the rule matches, logged as `tags`. New settings:
`SWW_TAG_LISTS`, `SWW_TAG_DENY`, `SWW_TAG_LIMIT_PERCENT`. They replace
`SWW_ASN_LIMIT_PERCENT`, `SWW_COUNTRY_LIMIT_PERCENT` and
`SWW_DENIED_COUNTRIES`. New heuristics `tag_lists` and `tag_deny`; the
latter runs before the rate limits and again after the Core Rule Set.

Model: opus-5-5

internal/discriminator/crowdsec.go

@@ -13,9 +13,9 @@ import (
 )
 
 // crowdSec refuses a request when a decision of the CrowdSec decision list on
-// the client is in force at now. It then notes the list, as noteHit does, and
-// bans the client until that decision ends. Its figures are the decision's
-// scenario and when it ends.
+// the client is in force at now. It then adds the tag crowdsec, notes the
+// list, as noteHit does, and bans the client until that decision ends. Its
+// figures are the decision's scenario and when it ends.
 type crowdSec struct{}
 
 func (crowdSec) name() string { return "crowdsec" }
@@ -26,6 +26,7 @@ func (crowdSec) check(_ context.Context, rq *request, now time.Time) *verdict {
 		return nil
 	}
 
+	rq.addTag("crowdsec")
 	rq.noteHit(bans.ReputationHit{Source: rq.h.config.CrowdSecDecisionsURL},
 		"listed by the CrowdSec decision list")
 	rq.banForCrowdSec(now, decision)