Add initial Microsoft Teams support

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

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

@@ -0,0 +1,11 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// AttendeeBase undocumented
+type AttendeeBase struct {
+	// Recipient is the base model of AttendeeBase
+	Recipient
+	// Type undocumented
+	Type *AttendeeType `json:"type,omitempty"`
+}