Show figures of the routing table on the home page (closes #154)

The home page gets cards for the newest and oldest kept route, the newest
and oldest updated AS, the AS with the most prefixes, the ASes with a
single prefix and fifteen well-known networks. Two more cards count the
bogon announcements and the prefixes with several origin ASes. They link
to the new pages /bogons and /multiple-origins, which list up to 1,000
entries each.

The new package internal/bogon tells reserved prefixes and AS numbers,
from the IANA special-purpose and address space registries. Table.Overview
walks the table and lets the read lock go every 10,000 prefixes. The
server works the cards out once a minute and serves that copy. A new index
on asns(last_seen) finds the newest and oldest updated AS.

Model: opus-5-5

internal/templates/templates.go

@@ -27,6 +27,12 @@ var prefixDetailHTML string
 //go:embed prefix_length.html
 var prefixLengthHTML string
 
+//go:embed bogons.html
+var bogonsHTML string
+
+//go:embed multiple_origins.html
+var multipleOriginsHTML string
+
 // Templates contains all parsed templates
 type Templates struct {
 	// Index is the template for the home page
@@ -39,6 +45,11 @@ type Templates struct {
 	PrefixDetail *template.Template
 	// PrefixLength is the template for displaying prefixes by length
 	PrefixLength *template.Template
+	// Bogons is the template of the page that lists the bogon announcements
+	Bogons *template.Template
+	// MultipleOrigins is the template of the page that lists the prefixes
+	// announced by more than one origin AS
+	MultipleOrigins *template.Template
 }
 
 var (
@@ -116,6 +127,18 @@ func initTemplates() {
 	if err != nil {
 		panic("failed to parse prefix length template: " + err.Error())
 	}
+
+	defaultTemplates.Bogons, err = template.New("bogons").
+		Funcs(funcs).Parse(bogonsHTML)
+	if err != nil {
+		panic("failed to parse bogons template: " + err.Error())
+	}
+
+	defaultTemplates.MultipleOrigins, err = template.New("multipleOrigins").
+		Funcs(funcs).Parse(multipleOriginsHTML)
+	if err != nil {
+		panic("failed to parse multiple origins template: " + err.Error())
+	}
 }
 
 // Get returns the singleton Templates instance
@@ -149,3 +172,14 @@ func PrefixDetailTemplate() *template.Template {
 func PrefixLengthTemplate() *template.Template {
 	return Get().PrefixLength
 }
+
+// BogonsTemplate returns the parsed template of the bogon announcements page
+func BogonsTemplate() *template.Template {
+	return Get().Bogons
+}
+
+// MultipleOriginsTemplate returns the parsed template of the page of prefixes
+// announced by more than one origin AS
+func MultipleOriginsTemplate() *template.Template {
+	return Get().MultipleOrigins
+}