Add initial Microsoft Teams support

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

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

@@ -0,0 +1,36 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// ChatMessageImportance undocumented
+type ChatMessageImportance string
+
+/*
+
+const (
+	// ChatMessageImportanceVNormal undocumented
+	ChatMessageImportanceVNormal ChatMessageImportance = 0
+	// ChatMessageImportanceVHigh undocumented
+	ChatMessageImportanceVHigh ChatMessageImportance = 1
+	// ChatMessageImportanceVUrgent undocumented
+	ChatMessageImportanceVUrgent ChatMessageImportance = 2
+)
+
+// ChatMessageImportancePNormal returns a pointer to ChatMessageImportanceVNormal
+func ChatMessageImportancePNormal() *ChatMessageImportance {
+	v := ChatMessageImportanceVNormal
+	return &v
+}
+
+// ChatMessageImportancePHigh returns a pointer to ChatMessageImportanceVHigh
+func ChatMessageImportancePHigh() *ChatMessageImportance {
+	v := ChatMessageImportanceVHigh
+	return &v
+}
+
+// ChatMessageImportancePUrgent returns a pointer to ChatMessageImportanceVUrgent
+func ChatMessageImportancePUrgent() *ChatMessageImportance {
+	v := ChatMessageImportanceVUrgent
+	return &v
+}
+*/