New provider: Loopia DNS service provider (#2140)

Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

providers/loopia/auditrecords.go

@@ -0,0 +1,31 @@
+package loopia
+
+import (
+	"fmt"
+	"github.com/StackExchange/dnscontrol/v3/models"
+	"github.com/StackExchange/dnscontrol/v3/pkg/rejectif"
+)
+
+// AuditRecords returns a list of errors corresponding to the records
+// that aren't supported by this provider.  If all records are
+// supported, an empty list is returned.
+func AuditRecords(records []*models.RecordConfig) []error {
+	a := rejectif.Auditor{}
+
+	a.Add("TXT", rejectif.TxtIsEmpty) // Last verified 2023-03-10: Loopia returns 404
+
+	//Loopias TXT length limit appears to be 450 octets
+	a.Add("TXT", TxtHasSegmentLen450orLonger)
+
+	return a.Audit(records)
+}
+
+// TxtHasSegmentLen450orLonger audits TXT records for strings that are >450 octets.
+func TxtHasSegmentLen450orLonger(rc *models.RecordConfig) error {
+	for _, txt := range rc.TxtStrings {
+		if len(txt) > 450 {
+			return fmt.Errorf("%q txtstring length > 450", rc.GetLabel())
+		}
+	}
+	return nil
+}