feat: implement caldav search

vendor/github.com/dolanor/caldav-go/icalendar/values/csv.go

@@ -0,0 +1,24 @@
+package values
+
+import (
+	"log"
+	"strings"
+)
+
+var _ = log.Print
+
+type CSV []string
+
+func (csv *CSV) EncodeICalValue() (string, error) {
+	return strings.Join(*csv, ","), nil
+}
+
+func (csv *CSV) DecodeICalValue(value string) error {
+	value = strings.TrimSpace(value)
+	*csv = CSV(strings.Split(value, ","))
+	return nil
+}
+
+func NewCSV(items ...string) *CSV {
+	return (*CSV)(&items)
+}