Add initial Microsoft Teams support

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

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

@@ -0,0 +1,29 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+import "time"
+
+// ExternalFile undocumented
+type ExternalFile struct {
+	// ExternalItem is the base model of ExternalFile
+	ExternalItem
+	// CreatedDateTime undocumented
+	CreatedDateTime *time.Time `json:"createdDateTime,omitempty"`
+	// ModifiedDateTime undocumented
+	ModifiedDateTime *time.Time `json:"modifiedDateTime,omitempty"`
+	// CreatedBy undocumented
+	CreatedBy *string `json:"createdBy,omitempty"`
+	// LastModifiedBy undocumented
+	LastModifiedBy *string `json:"lastModifiedBy,omitempty"`
+	// Title undocumented
+	Title *string `json:"title,omitempty"`
+	// URL undocumented
+	URL *string `json:"url,omitempty"`
+	// Name undocumented
+	Name *string `json:"name,omitempty"`
+	// Extension undocumented
+	Extension *string `json:"extension,omitempty"`
+	// Size undocumented
+	Size *int `json:"size,omitempty"`
+}