Add Toot timestamps to toot_fetched event in mastodonbee

Now the toot_fetched event also returns a timestamp of the toot.
As we can already delete toots by ID this change can be used for more complex
chains with mastodon. E.g. Automatically remove toots from your timeline after X
days.
This resolves #247

bees/mastodonbee/events.go

@@ -70,6 +70,11 @@ func (mod *MastodonBee) handleStatus(status *mastodon.Status) {
 				Value: status.URL,
 				Type:  "string",
 			},
+			{
+				Name:  "created",
+				Value: status.CreatedAt,
+				Type:  "time.Time",
+			},
 		},
 	}
 	mod.evchan <- ev

bees/mastodonbee/mastodonbeefactory.go

@@ -156,6 +156,11 @@ func (factory *MastodonBeeFactory) Events() []bees.EventDescriptor {
 					Description: "The url for the toot",
 					Type:        "string",
 				},
+				{
+					Name:        "created",
+					Description: "The timestamp of the toots creation",
+					Type:        "time.Time",
+				},
 			},
 		},
 		{