release: 0.6.0: Delivery detail page, DNS badge, machine metrics, wide layout

A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
Added:
  - A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
  - A **DNS** badge in the domain list, one per row, carrying the same
  - Machine metrics on the status page: a **Machine** card reporting the
  - An index of the current page's own sections in the navigation column, for the
Changed:
  - Every panel page is laid out in one column of the same width, so moving
  - The mark's small-size variant — the tab icon and the `SP` initials it
  - The stamp's `SELF-HOSTED SMTP RELAY` line is set at 11.5/0.15 instead of
  - The delivery log lists what identifies a message and nothing else: time,
  - Subjects are decoded for display as well as on the way in, so the rows the
  … (4 more in CHANGELOG)

Full detail: CHANGELOG.md (0.6.0).

internal/web/templates.go

@@ -35,6 +35,7 @@ var pageFiles = map[string][]string{
 	"domain_detail": {"templates/domain_detail.html", "templates/encrypt_fields.html"},
 	"domain_delete": {"templates/domain_delete.html"},
 	"deliveries":    {"templates/deliveries.html", "templates/deliveries_rows.html"},
+	"delivery":      {"templates/delivery.html"},
 	"mail_queue":    {"templates/mail_queue.html", "templates/mail_queue_body.html"},
 	"system_log":    {"templates/system_log.html", "templates/system_log_body.html"},
 	"status":        {"templates/status.html", "templates/status_body.html"},