Remove the CrowdSec decision feed (closes #315)

sneak ruled to remove it. Gone: the heuristic crowdsec, the ban cause
crowdsec and its earlier_bans count, the tag crowdsec, the settings
SWW_WAF_CROWDSEC_LAPI_URL and SWW_WAF_CROWDSEC_LAPI_KEY, the decision
list fetch and parse in internal/reputation, their tests, and every
mention in the README, SPEC.md and docs/. EVALUATION.md keeps its
comparison of tools.

The ban ledger's internal ban function loses its expires parameter,
which only CrowdSec bans used.

Model: opus-5-5

internal/alerts/alerts.go

@@ -48,9 +48,8 @@ const (
 	// SWW_WAF_CORE_RULE_SET_SCORE_THRESHOLD, refused in block mode, let through in
 	// detect mode.
 	EventCoreRuleSetMatch = "core_rule_set_match"
-	// EventReputationHit is a request whose client a blocklist, the
-	// CrowdSec decision list or a DNSBL zone lists, or whose AbuseIPDB score
-	// is a hit.
+	// EventReputationHit is a request whose client a blocklist or a DNSBL
+	// zone lists, or whose AbuseIPDB score is a hit.
 	EventReputationHit = "reputation_hit"
 	// EventSourceFailure is GeoJS failing or refusing sww, a fetch
 	// of a list failing, a query to a DNSBL zone or a check with AbuseIPDB