Ban notes name the reputation sources that listed the client (closes #109)

A ban's notes, in bans.json and in its alert, gain `reputation`: each
blocklist, DNSBL zone or AbuseIPDB that listed the client when the ban
was made, as its `source`, named and ordered as in the request log's
`reputation`, with AbuseIPDB's `score`. It is left out when none did.
README.md shows it in a bans.json example.

Notes now hold a list, so bans can no longer be compared with ==: the
tests compare them with reflect.DeepEqual.

Judgement call: the score is a pointer, so a score of 0, a hit while
SWWAF_ABUSEIPDB_MIN_SCORE is 0, is still written.

Model: opus-5-5

internal/bans/admin_test.go

@@ -2,6 +2,7 @@ package bans_test
 
 import (
 	"net/netip"
+	"reflect"
 	"testing"
 	"time"
 
@@ -117,7 +118,7 @@ func TestLiftedBanForALimitRefusesNothingAndMakesNoBanLonger(t *testing.T) {
 	}
 
 	held := ledger.Bans(netblock)
-	if len(held) != 2 || held[0] != lifted {
+	if len(held) != 2 || !reflect.DeepEqual(held[0], lifted) {
 		t.Errorf("the ledger holds %+v, want the lifted ban and the new one", held)
 	}
 }
@@ -212,7 +213,7 @@ func TestAdminsBanIsMadeWhileAnotherLasts(t *testing.T) {
 
 	got := ledger.BanForAdmin(netip.MustParsePrefix("203.0.113.9/24"), now, time.Time{},
 		"probes for logins")
-	if got != want {
+	if !reflect.DeepEqual(got, want) {
 		t.Errorf("the admin's ban is\n%+v\nwant\n%+v", got, want)
 	}
 
@@ -224,7 +225,7 @@ func TestAdminsBanIsMadeWhileAnotherLasts(t *testing.T) {
 
 	// It refuses once the ban for the limit has ended.
 	ban, banned, _ := ledger.Find(netblock.Addr(), midnight().Add(2*time.Hour))
-	if !banned || ban != want {
+	if !banned || !reflect.DeepEqual(ban, want) {
 		t.Errorf("after the limit's ban the netblock is under %+v (%t), want %+v",
 			ban, banned, want)
 	}