feat: send polls (#2377)

* feat: added Poll class

* feat: logic for sending polls added

* updated poll properties on returned message instance

* docs updated

* usage example updated

* module fixed

* 'pollSendOptions' changed to 'options'

* window.compareWwebVersions fixed

* small update to improve the performance of findImpl fix

* added option for custom message secret

* usage example updated

index.js

@@ -18,6 +18,7 @@ module.exports = {
     BusinessContact: require('./src/structures/BusinessContact'),
     ClientInfo: require('./src/structures/ClientInfo'),
     Location: require('./src/structures/Location'),
+    Poll: require('./src/structures/Poll'),
     ProductMetadata: require('./src/structures/ProductMetadata'),
     List: require('./src/structures/List'),
     Buttons: require('./src/structures/Buttons'),