Store and show an event's query string, and pass it on to an HTTP target when set (closes #312)

The receiver dropped the query string of every request it received, so a sender's URL parameters were silently lost. Each event now keeps it, as sent, in a new `raw_query` column of the per-webhook `events` table; a resubmitted copy carries its original's. The event log and the event's page show it in the shared request block, the event log leaving out one over 32 KiB with a link, as for headers. The archive and log targets carry it. HTTP targets gain "Pass the query string on to this target", off by default: on, deliveries, replays and resubmits append it to the target URL, joined with `&` to one already there. The access log still hides it.

Model: opus-5-5

internal/delivery/target_database_test.go

@@ -85,6 +85,7 @@ func TestDeliverDatabase_ArchivesEvent(t *testing.T) {
 
 	webhookDB := testWebhookDB(t)
 	event := seedEvent(t, webhookDB, `{"archived":true}`)
+	event.RawQuery = eventQuery
 	d := seedDatabaseTargetDelivery(t, webhookDB, event, tgt)
 
 	env.eng.ExportDeliverDatabase(webhookDB, d)
@@ -113,6 +114,7 @@ func TestDeliverDatabase_ArchivesEvent(t *testing.T) {
 	assert.Equal(t, event.ID, rows[0].EventID)
 	assert.Equal(t, event.WebhookID, rows[0].WebhookID)
 	assert.Equal(t, event.Method, rows[0].Method)
+	assert.Equal(t, eventQuery, rows[0].RawQuery)
 	assert.JSONEq(t, `{"archived":true}`, rows[0].Body)
 }