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

Each request gets tags, logged as `tags`: `asn=`, `country=`, one per `SWW_TAG_LISTS` list holding the client, `crowdsec`, `dnsbl=<zone>`, `abuseipdb` and `exploitsignature`. `SWW_TAG_DENY` refuses by tag and `SWW_TAG_LIMIT_PERCENT` lowers limits by tag. They replace `SWW_ASN_LIMIT_PERCENT`, `SWW_COUNTRY_LIMIT_PERCENT` and `SWW_DENIED_COUNTRIES`, with no aliases. A tag in those settings that nothing configured can give stops the start.

Judgement call: `SWW_ASN_LIMIT_PERCENT_URL` stays, its entries counting like `asn=` tags.
Judgement call: `SWW_TAG_LIMIT_PERCENT` also lowers byte limits, as the settings it replaces did.
Trips a reader: `sww_country_list_refusals_total` now counts only `SWW_EXCLUSIVELY_ALLOWED_COUNTRIES` refusals.

Model: opus-5-5

internal/discriminator/crowdsec.go

@@ -8,14 +8,15 @@ import (
 	"time"
 
 	"sneak.berlin/go/smallwebwaf/internal/bans"
+	"sneak.berlin/go/smallwebwaf/internal/config"
 	"sneak.berlin/go/smallwebwaf/internal/reputation"
 	"sneak.berlin/go/smallwebwaf/internal/requestlog"
 )
 
 // 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 +27,7 @@ func (crowdSec) check(_ context.Context, rq *request, now time.Time) *verdict {
 		return nil
 	}
 
+	rq.addTag(config.CrowdSecTag)
 	rq.noteHit(bans.ReputationHit{Source: rq.h.config.CrowdSecDecisionsURL},
 		"listed by the CrowdSec decision list")
 	rq.banForCrowdSec(now, decision)