feat: implement caldav search

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

@@ -0,0 +1,32 @@
+package entities
+
+import (
+	"encoding/xml"
+)
+
+// a property of a resource
+type Prop struct {
+	XMLName        xml.Name      `xml:"DAV: prop"`
+	GetContentType string        `xml:"getcontenttype,omitempty"`
+	DisplayName    string        `xml:"displayname,omitempty"`
+	ResourceType   *ResourceType `xml:",omitempty"`
+	CTag           string        `xml:"http://calendarserver.org/ns/ getctag,omitempty"`
+	ETag           string        `xml:"http://calendarserver.org/ns/ getetag,omitempty"`
+}
+
+// the type of a resource
+type ResourceType struct {
+	XMLName    xml.Name                `xml:"resourcetype"`
+	Collection *ResourceTypeCollection `xml:",omitempty"`
+	Calendar   *ResourceTypeCalendar   `xml:",omitempty"`
+}
+
+// A calendar resource type
+type ResourceTypeCalendar struct {
+	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:caldav calendar"`
+}
+
+// A collection resource type
+type ResourceTypeCollection struct {
+	XMLName xml.Name `xml:"collection"`
+}