Add initial Microsoft Teams support

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

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

@@ -0,0 +1,13 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// CustomAction undocumented
+type CustomAction struct {
+	// InformationProtectionAction is the base model of CustomAction
+	InformationProtectionAction
+	// Name undocumented
+	Name *string `json:"name,omitempty"`
+	// Properties undocumented
+	Properties []KeyValuePair `json:"properties,omitempty"`
+}