Add initial Microsoft Teams support

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

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

@@ -0,0 +1,23 @@
+// Code generated by msgraph-generate.go DO NOT EDIT.
+
+package msgraph
+
+import "time"
+
+// Conversation undocumented
+type Conversation struct {
+	// Entity is the base model of Conversation
+	Entity
+	// Topic undocumented
+	Topic *string `json:"topic,omitempty"`
+	// HasAttachments undocumented
+	HasAttachments *bool `json:"hasAttachments,omitempty"`
+	// LastDeliveredDateTime undocumented
+	LastDeliveredDateTime *time.Time `json:"lastDeliveredDateTime,omitempty"`
+	// UniqueSenders undocumented
+	UniqueSenders []string `json:"uniqueSenders,omitempty"`
+	// Preview undocumented
+	Preview *string `json:"preview,omitempty"`
+	// Threads undocumented
+	Threads []ConversationThread `json:"threads,omitempty"`
+}