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/bans_test.go

@@ -211,7 +211,7 @@ func TestBannedClientIsRefusedBeforeItsCountryIsLookedUp(t *testing.T) {
 		lookupTimeout:      "1h",
 		rateLimitPerMinute: "1",
 		banScopeV4Prefix:   "24",
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 	})
 
 	// fromDE's ban covers otherClient, which is refused unasked about.
@@ -266,7 +266,7 @@ func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 				lookupTimeout:      "1h",
 				rateLimitPerMinute: "1",
 				denyNets:           denied,
-				deniedCountries:    "kp",
+				tagDeny:            denyKP,
 			}
 
 			if tc.setting != "" {
@@ -276,7 +276,7 @@ func TestBanResponseAnswersEveryRefusalButTheSizeLimits(t *testing.T) {
 			s, _, _ := startWithClock(t, geojsURL, env)
 
 			s.get(denied, tc.status, requestlog.ActionDenied)
-			s.get(fromKP, tc.status, requestlog.ActionCountryDenied)
+			s.get(fromKP, tc.status, requestlog.ActionDenied)
 			s.get(fromDE, http.StatusOK, requestlog.ActionForward)
 			s.get(fromDE, tc.status, requestlog.ActionRateLimited)
 			s.get(fromDE, tc.status, requestlog.ActionBanned)
@@ -291,7 +291,7 @@ func TestBanNotes(t *testing.T) {
 	s, clk, server := startWithClock(t, geojsURL, map[string]string{
 		lookupTimeout:      "1h",
 		rateLimitPerMinute: "1",
-		deniedCountries:    "kp",
+		tagDeny:            denyKP,
 	})
 	start := clk.Now()