Add initial Microsoft Teams support

Documentation on https://github.com/42wim/matterbridge/wiki/MS-Teams-setup

vendor/github.com/yaegashi/msgraph.go/beta/ItemPreviewInfoModel.go

@@ -0,0 +1,15 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// ItemPreviewInfo undocumented
+type ItemPreviewInfo struct {
+	// Object is the base model of ItemPreviewInfo
+	Object
+	// GetURL undocumented
+	GetURL *string `json:"getUrl,omitempty"`
+	// PostParameters undocumented
+	PostParameters *string `json:"postParameters,omitempty"`
+	// PostURL undocumented
+	PostURL *string `json:"postUrl,omitempty"`
+}