feat: implement caldav search

vendor/github.com/dolanor/caldav-go/caldav/entities/prop.go

@@ -0,0 +1,23 @@
+package entities
+
+import (
+	"encoding/xml"
+	"github.com/dolanor/caldav-go/webdav/entities"
+)
+
+// a CalDAV Property resource
+type Prop struct {
+	XMLName        xml.Name               `xml:"DAV: prop"`
+	GetContentType string                 `xml:"getcontenttype,omitempty"`
+	DisplayName    string                 `xml:"displayname,omitempty"`
+	CalendarData   *CalendarData          `xml:",omitempty"`
+	ResourceType   *entities.ResourceType `xml:",omitempty"`
+	CTag           string                 `xml:"http://calendarserver.org/ns/ getctag,omitempty"`
+	ETag           string                 `xml:"http://calendarserver.org/ns/ getetag,omitempty"`
+}
+
+// used to restrict properties returned in calendar data
+type PropertyName struct {
+	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:caldav prop"`
+	Name    string   `xml:"name,attr"`
+}