Add initial Microsoft Teams support

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

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

@@ -0,0 +1,13 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// AddHeader undocumented
+type AddHeader struct {
+	// MarkContent is the base model of AddHeader
+	MarkContent
+	// Margin undocumented
+	Margin *int `json:"margin,omitempty"`
+	// Alignment undocumented
+	Alignment *Alignment `json:"alignment,omitempty"`
+}