Add initial Microsoft Teams support

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

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

@@ -0,0 +1,13 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+// Image undocumented
+type Image struct {
+	// Object is the base model of Image
+	Object
+	// Height undocumented
+	Height *int `json:"height,omitempty"`
+	// Width undocumented
+	Width *int `json:"width,omitempty"`
+}